LIBRARY OF CONGRESS. 



(SMITHSONIAN DEPOSIT.) 

Chap. T C I 5 3 

Shelf (F 6 



UNITED STATES OF AMERICA. 



CONTRIBUTIONS 



■JO THE 



SCIENCE OF HYDRAULIC ENGINEERING. 



BT 



'■- I 



•I 

PROFESSOR OP THEOLOGY AND NATURAL SCIENCE, MEMBER OF THE NEW TORE HISTORICAL SOCIETY, 

THE HISTORICAL SOCIETY OF MARYLAND, &r., AND OF THE ACADEMIES OF SCIENCE OF 

BALTIMORE, NEW ORLEANS, &C., AUTHOR OF "HOW THE WORLD WAS PEOPLED,'' &c. 




WASH I NGTON : 

G ( ) V K li N M E N r PRINTING O F F I O K 
1879. 



I If. 



..^^•■' 






\ 



O 



^ 



V 



\9 



/ 



I^REFi^CE 



I thought first of presenting the following contributions to the science of Hydraulic Engineer- 
ing in the usual form of a plain methodical work for the instruction of students. But certain 
objections suggested by the recollection of my painful exijerience in the stiidy of such treatises 
inclined me to give it to them in a composition which they will find more entertaining, and I hope 
equally instructive. 

It is usual for text-books, and especially those of the exact sciences for the use of schools, to be 
divested of all the adornments of fancy. They aim at conciseness of style, and smallness of bulk. 
Such books may be cheap and marketable, but they are exceedingly dry and uninteresting ; and 
they are difficult to understand and easily forgotten. Arithmetics, Algebras, Geometries, and the 
text-books on Civil and Military Engineering, and Navigation, and even treatises on the most 
sublime of all the physical sciences. Astronomy^ used in our Military and Naval Academies, and all 
our institutions of learning, almost without an exception are of this dry, stony, and icy character, 
utterly devoid of every tint and trait of beaitty which can attract the attention, charm the imag- 
ination, and impress the memory. When I was a youth 1 studied Horner's Anatomy; and the 
ludicrous plainness of his descriptions of the wonderful details of the material tenement of the 
immortal soul amused me. But why should not a book descriptive of bones be "dry as a bone"! 
And what room for "the play of fancy" is there in a treatise on "the theory of curves""? The 
writers of such works are hardly capable of giving a correct answer, for they are usually totally 
devoid of the poetical faculty, as the imaginative youths who are forced to study them know to 
their sorrow. It is generally the severest toil and torture of their ardent young lives ; and through 
all their future years the most brilliant genitises among them look back upon the ordeal of their 
mathematical course with horror. The fault is in the writers of the text-books, and not in the 
noble sciences which they dissect, skeletonize, and present in modes the most ghastly and repulsive. 
The disciples of Euclid, Archimedes, and Newton might make their books a little more pleasing by 
a few anecdotes of these great men illustrating their discoveries, and by adding a few observations 
directing attention to the important uses to which their sublime i^roblems may be applied. Elihu 
Burritt has ^\^:•itten a really learned and agreeable text-book on Astronomy. Sir William Jones? 
in his treatise on " Bailments," has proven how interesting one of the very dryest of all the sub- 
jects of the common and statute law of England may be rendered by a writer of genius. Richerand 
made the study of human physiology attractive. Cuvier exhumed the fossil bones of the extinct 
mammalia, and robed the ancient rocks in which they were buried before " the flood " with the 
radiance of a resurrected world. Fortunately the classic historians and poets of ancient Greece 
and Rome are yet studied as text-books in our academies and colleges ; and the boy who quickly 
forgets all that he learned with diflaculty of "quadratic equations" and "conic sections" will 
remember forever the delightful narratives of Cfesar and Xenophon, tlie orations of Cicero and 
Demosthenes, and the lays of Virgil and Homer. 

It should never be forgotten by those who write books which they intend to be read and 
remembered, that aU minds grasp and comprehend most easily, and aU memories retain most 



4 PREFACE. 

tenaciously, whatever is most exciting and pleasing to the imagination. This must be my excuse 
for whatever of " the poetry of science " may appear in these brief lectures. The unpoetical mathe- 
matician would i^refer the subjects embraced by them presented in the forms of skeletonized dia- 
grams and problems bristling with algebraic signs, and geometric angles, tangents, and curves. 
He cannot discern the beauty, or discover the use of "the fi-oth and foam " and the bubbles which 
glitter with prismatic hues upon the Mississippi's mammoth tide, and he looks with contempt uj)on 
the lilies and loli which sparkle upon the bosoms of the placid lakes, and fails to see the gorgeous 
and lovely profusion of foliage and flowers which wreathe and veil their banks and shores. He 
prefers by the four rules of the science of numbers to estimate the cubic inches of water which 
they contain, or the precise amount of the mud which causes their turbidity or forms their deposits. 
I admire the liatient toil and useful taste for calculation of oiu' practical operative mathematicians; 
and I am exceedingly anxious to see them engaged in the useful task of applying the hydraulic 
plans suggested in these lectures. They delight in making all the estimates of the cost of the 
materials and of the labor which their application will require in all its details, and which I have 
carefully omitted. My object has been to give plain and palpable outlines of plans very necessary 
for our welfare, the details of which any practical mathematician can supply, and which any effi- 
cient mechanic can execute withimt understanding the technical terms of science. 

I have another benevolent object in view in i)reseuting these important and easily applied 
principles of hydraulics in the simi)le form of lectures, precisely as I delivered them in aSTew 
Orleans. If the General and State governments of our country should long procrastinate, or neglect 
entirely the api^lication of proper plans for the drainage and irrigation of our public alluvial lands, 
and the prevention of their overflows, in many instances corporations or individuals who own such 
lands may imi^rove them without the aid of either the Federal or State government, if they have 
the ability to utilize the directions I have given them. Although they may not be able to remove 
the obstructions to the navigation of the rivers which are the property of the United States, and 
which it is the exclusive duty of the General Government to improve, individuals have the right 
to i^revent the inundation of their own lands, and to drain and irrigate them if they have the power 
and choose to exercise it. 

The science of Hydraulic Engineering as api)lied to the control of water-currents has not kept 
pace with the march of this age of progress, and but few additions have been made to the text- 
books embracing this department of Civil Engineering which were taught in our institutions of 
earning thirty years ago. I am not aware that any of them written before or since 1832 teach the 
principles explained in these lectures which I here present as a few contributions to assist the 
jjresent and future labors of hydraulic engineers. I hope that whatever is new and useful in them 
will find a place in the improved works which at no distant day will be prepared for students, and 
that they will apply it in improving the condition of our country and other lands. 

If any one who reads these essax s doubts whether the principles enunciated and the rules 
given to direct their application are nothing more than mere untried theories, I assure the skeptic 
that I have tested each one recommended by the most elaborate and careful experiments. Some 
of the most valuable discoveries were made while I was making experiments to apply practically 
and cheai)ly the principles and working plans of nature in utilizing water in motion. 



UMPEOV^ED METHODS 



OF 



HYDRAULIC ENGINEERING. 



FOE 



CONTROLLING AND UTILIZING WATER CURRENIS, 



AND 



ITS GENERAL APPLICATION 



^Jso, its specific appliance- 



IST, TO DRAINAGE AND IREIGATION ; 

2d, to the improvement of LAKES AND HARBORS: AND, 

3d, to a general LEVEE SYSTEM CONNECTED WITH JETTIES, TO GIVE PERMANENCE 
TO BANKS AND SHORES, TO REMOVE BARS, SHOALS, AND OTHER OBSTRUCTIONS TO NAVIGATION, 
AND TO GIVE FIXEDNESS TO THE BEDS OF RIVERS, AND SO TO DEEPEN THEM AS TO PREVENT 
OVERFLOWS. 

BT 

EWD. FOlSTT^nSTE. 



INTRODUCTORY ESSAY 

ADDEESSED TO THE PEOPLE OF THE CITY OF NEW OELEANS, LA. 

[The introduction and the whole of the subjects embraced in this pamphlet were delivered by invitation to the 
New Orleans Academy of Sciences in three lectures, November'27 and December 4 and 11, 1877.] 



A PLAN FOR DRAUfOG THE CITY OF NEW ORLEANS, AND FOR PREVENTING ITS INUN- 
DATION BY THE LAKES AND THE MISSISSIPPI RIVER. 

The greatest obstruction to the prosperity of New Orleans is the danger to the lives and 
property of its citizens, caused hj^ the inundations and epidemics which have afflicted it, and with 
which it is continually threatened. The great river, varying in width from a half mile to a mile in 
the city, flows through it in an ever-changing channel caused by its Titanic current. The average 
depth of this vast volume of fresh water from Baton Eouge to-" the Passes" is about 100 feet, and 
its mean velocity is 4 miles per hour. Within the city its surface at the lowest stage of its water- 
level is only 5 feet above that of the Atlantic Ocean, the Gulf of Mexico, and the adjacent lakes 
connected with it, and which rise and fall with the oscillations of its tides and storms. During the 
period of its greatest floods the surface of the river is elevated about 15 feet above that of the 
Gulf. The extreme variation of its surface level is about 10 feet. Its velocity corresponds exactly 
with the volume of its water or the oscillations of its surface. During the acme of its flood it 
flows with the fearful speed of 5 miles per hour. AVhen at its lowest stage, and in its most atten- 
uated condition, its course is slackened to 3 miles per hour. Its average velocity is about 4 miles 
per hour. 

A peculiarity of the current of the Mississippi which is too often disregarded by those who 
live upon its banks, and by the engineers who attempt to secure them against undermines and 
overflows, is the alarming fact that it flows as siviftly at its bottom, or upon the deepest depressions of 
its bed, as it does upon the sides of its crumbling banJcs, or at its surface ! Numerous experiments 
made by the most competent engiueers of the United States Army have demonstrated this singular 
fact. Immense water-logged trunks of trees and large masses of tenacious clay have been found 
by them rolling and sliding upon the bottom of the river in the channel where it is deepest, and 
10^ feet belotc the surface of the (tm I/, propelled towards it by this gigantic current with a velocity 
equal to that which moves the light driftwood floating upon its waves. Sometimes the bottom cur- 
rent is hurled by some obstruction to the top, where it svvells above the surface level and rolls 
away in angry eddies. It is this bottom current, acting under the pressure of the immense depth 
and weight of the fluid-moviug-mass above it against the deep sand strata underlying the layers 
of clay and other materials which compose its banks, and the whole alluvial Delta, Avhich causes 
all the disasters of crevasses, inundations, and the engulfing of plantations and human abodes, 
and which continually menaces this city with destruction. One of the most distinguished engi- 
neers and soldiers whom Louisiana has produced. General G. T. Beauregard, can testify that he 
found with the sounding-line two spots directly in the current at the time he was making his 
observations on the cross-sections of the river near the Third District Ferry, each 240 feet deep. 

The cross-sections marked on Harrison's map of the city in 1846, in the Academy of Sciences, 
and which w^as used by the engineers before the civil war as the best topographical authority, dem- 
onstrate the same appalling truth in regard to the tremendous undermining and excavating force 
of the bottom current of the Mississippi. At the time it was making the enormous area of batture 



8 • CONTRIBUTIONS TO THE 

between Tchoui^itoulas street and New Levee street, it was excavating trenches on the right bank 
162 feet deep, and filling up others which it had dug out under the left bank, now covered with 
great blocks of buildings, 182 feet deep. The same mammoth force is now undermining a mile of the 
Crescent City front with the bottom current deflected against it by the diagonal projection of the peninsula 
of Algiers. 

I give these disagreeable facts in regard to the physical geography of the foundation of New 
Orleans, and the peculiarities of the current of the mammoth river,. to /wc/t will certainly rearrange all 
of the materials which compose it, unless it shall be controlled, in order that the absurdity may be made 
obvious of building superficial levees, wharves, or houses upon the margin of the surface of the 
water, while this deep and terrific bottom current is left unchecked to undermine and engulf all the 
vain works of man erected upon stratified alluvium in which no rock is found even at a depth of 
630 feet ! And also that the minds of those most interested may be prepared to investigate the 
merits of the plan iiroposed in this essay for guarding them against this threatened danger. 

I will mention, in order to show that this danger is not imaginary, that I made a map for the 
Academy of Sciences while I was its secretary, and lecturer in tbe chair of geology, plotted from 
the boring of the Artesian well in Canal street, between Carondolet and Baronne, made in 1856, 
and superintended and accurately reported by a committee of the most comj)etent chemists and 
geologists of that institution, which is, I suj)pose, yet among its archives, an examination of which 
will show that the foundation of Neic Orleans rests upon no rod' for at least 630 feet ; but that the 
surface of the i-iver flows and the corner-stones of all the edifices of the city are laid above 57 strata 
of the most fragile and friable materials, irregularly distributed by the alternating and conflicting ■ 
currents of the ancient Mississippi and the Gulf of Mexico, and all the ujjper layers to a depth of 
200 feet have been rearranged by the modern river. 

In a lecture on the Physical Geography of the Mississipi^i, appended to my published work 
"How the World was Peopled," and the notes and diagrams added, p. 330, I have shown how the 
present river is acting its part as "a pigmy in giant's clothes" in rearranging the dejiosits made by 
its mammoth predecessor which drained the great mediterranean sea which existed after the glacial 
ei»och of which the large fresh-water lakes of the United States and British America are the remains, 
and which made the Delta of Louisiana. I have discussed this subject at greater length in a lecture 
delivered in Washington City to the two Houses of Congress, Ai)ril 30, 1874, published in a pamph 
let, on "The Peculiarities of the Physical Geography of the Mississippi River and its Delta," and 
the methods for removing the obstructions to the navigation of its mouths. 

One of these recent layers was so nearly _//mr? that the Artesian auger sunk into it 11 feet by 
its own weight! This rested upon more solid materials, beneath which, and 330 feet below the city, 
was an enormous stratum of sand, full of water like that of Bladon Springs, and which rose above 
the surface in an Artesian stream at the rate of six gallons per minute. This great sand-layer was 
140 feet thick! Underneath it were other strata of sand, clay, and mingled alluvial materials, 
one of them i)ure clay 60 feet thick. Yet all this stratified alluvium was not only post-tertiary but 
post-glacial in geological age, and so recent that none of the wood, shells, or other vegetable and 
animal matter which it contained was petrified or fossilized in any degree. At present there is 
no human device in oi^eratiou to prevent the bottom current of the river from ijenetrating and 
removing the whole of it, and sweeping it into the Gulf with everything erected upon it. 

In several lectures on the cause of the velocity of the current of the Mississippi River, and the 
direction of the great currents of the ocean, delivered in the New Orleans Academy of Sciences, I 
have, for the sake of scientific accuracy in the nomenclature of physical geography, termed those 
which fall from the equator towards the poles, like the Kui'o Siwoo or Black Current of the Pacific, 
the Madagascar of the Indian, and the Patagoniau and Gulf Streams of the Atlantic Oceans, cen- 
tripetal; and those which rise from the poles to the equator, like the Labiador and Corean from 
Davis's and Behring's Straits, centrifugal. 

While the great river thus menaces the foundations of the city with "sap and mine," the com- 
bined forces of the cyclones of the centripetal ocean current called the Gulf Stream, and the salt 
waves of Lakes Pontchartrain, Maurepas, and Borgne, threaten to "carry it by assault," and sweep 
it from the earth with wind and water "mingling in their might." 



SCIENCE OF HTDEAULIC El^GINEEEING. 9 

I do not like to be "a proiDliet of evil," and to lacerate the sensibilities of our afflicted people 
witli woeful Cassandriads or Jeremiads ; and I would not call their attention to another enemy whose 
fatal attacks are more dreaded by u.s than engulfment by the river, or destruction by the wings of 
the typhoon and the waves of the lakes, if I did not at the same time present them with a remedy 
to secure them. 

While "the Great Father of Waters" rolls through our city his fearful but yet beneficent sea 
of living and i)urifying water, dispensing health and wealth to all who will utilize his power and 
receive his gifts, and while he offers his services to irrigate and cleanse our city, and to pour into 
it the commerce and riches of all lands, threatening at the same time to scourge it if his proffered 
favors are spurned, on either hand lie dead lakes, bayous, lagoons, and bogs filled with stagnant 
and foetid fluid, and festering with pollution. Their arms, in the form of canals, ditches, and open 
gutters, green Avith scum, and mephitic with every form of microscopic animalcule, or vegetable 
alg8e or fungus, whose winged-eggs or invisible seed-spores ride upon the wings of the wind to spread 
malaria and death, penetrate every part of the city. These open elongated cesspools are the swords 
entering its vitals. All the filth of it enters them; and after an exposure to the face of the sun to 
shock all human eyes, and to offend all nostrils, its rank and mephitic odor is dilfused through the 
air, which it makes deadly with cholera, yellow fever, and all the forms of malarial disease which 
compounded filth can generate in Serbonian bog or Stygian lake. 

Wise men are guided by their own eyes, and follow their own noses. Our Creator has given us 
noses to guide us. Whatever offends the nose warns us to remove it or get away from it. These 
open gutters, sluggish canals, and stagnant ditches and slimy ponds are disgusting to the sight 
and sickening to the smell. Their evaporation is deadly Avernian fog. They ought to be dried 
up, or piped and covered under ground, to be seen and smelt no more. They are the principal 
sources of our ei>idemics. 

I repeat emphatically the assertion with which I commenced this essay, that the danger to the 
property and lives of our citizens caused by the sudden submergences of its banks by the perpetually 
shifting and undermining bottom current of the Mississippi, the continually recurring inundations 
of the city by the swells of the lakes, produced by the cyclones of the Gulf of Mexico, and the 
epidemic fevers generated by the stagnant water and undrained pollution of its site, are the main 
obstacles to its growth and prosperity. Bad government has lent its aid to these destructive agen- 
cies. But no matter what beneficent civil revolutions may occur in our city and State, the ruling 
powers of neither can escape the reproach of negligence, ijarsimony, stupidity, a disregard of the 
public weal, and whatever else, apart from theft, robbery, and murder, constitutes had government, 
who permit these obstacles to the prosperity of New Orleans to continue. They drive thousands 
from it who come to live in it. Unable to endure these nuisances and perils, they leave it with their 
families, and carry their capital and business to safer and more pleasant cities. They prevent the 
settlement of hundreds of thousands of refined and intelligent people and the investment of many 
millions of dollars in New Orleans. They give all the most enliglitened and virtuous citizens who 
are compelled by circumstances to live in it an aversion to their abode. They cripple or destroy 
schools and churches, as well as manufactories and business establishments of all kinds. No intel- 
ligent and affectionate parents are willing to live and labor, educate their children, and plant their 
posterity where their eyes are ijerpetually haunted with hideous rills and pools of filth, and their 
nostrils filled by day and night with abominable smells ; and where they and their offspring are 
liable at any time to die of some form of fever generated by foul putrescence, to be swallowed by 
the subterranean current of the Mississippi, or drowned by a flood from Lake Pontchartrain. Thus 
the fire of patriotism is quenched, and all the useful and magnificent works which only patriots 
perform for the utility and glory of the homes of their nativity or adoption are prevented. But few 
people, whether native or immigrant citizens, love New Orleans, or regard it as their permanent 
abode, or the future home of their posterity. The most of her residents consider it as a temporary 
locum tenendum, and a place only to be occupied while the necessity endures which compels them 
to brave its nuisances and dangers. They are determined to go with their families, as soon as they 
can, to live and die in some cleaner and less endangered city. 
2 H E 



10 CONTRIBUTIONS, ETC. 

The plan which I jiropose for abating these nuisances and removing these threatening and attack- 
ing perils would effect a radical metamorphosis in the physical condition of the city, and a change 
as thoroughly beneficent in the sentiments, morals, character, and circumstances of its inhabitants. 
It would transform all the virtuous and intelligent among them into patriots blessed with health 
and prosperity, willing to live and labor for a home which they would love as their only cherished 
earthly abode, and which would be the most favored, lovely, and magnificent city beneath the sky. 

Lake Pontchartrain must not be used for the drainage of the city. All bayous and canals 
intersecting it must be separated from this lake. While the connection between them exists all 
drainage plans for health and safety from overflows will be worthless and perilous. 



IP^E/T I. 



DRAINAGE AND IRRIGATION 



BY 



ekm:xjzesis: 



ITS GENERAL APPLICATION TO ALL MARSHY AND OVERFLOWED LANDS INTERSECTED BY RUNNING 

WATER, OR NEAR TO NATURAL OR ARTIFICIAL WATER-CURRENTS, WHOSE BOTTOMS ARE 

LOWER THAN THE BEDS OF THE SWAMPS AND SHALLOW LAKES TO BE DRAINED, 

AND ITS SPECIFIC APPLIANCE TO THE DRAINAGE AND WATER-SUPPLY OF 

THE CITY OF NEW ORLEANS AND THE SWAMP-LANDS OF LOUISIANA. 



PART I. 

DRAINAGE AND IRRIGATION. 



I present this connected plan, consisting of three parts, as a whole system which is constructed 
to suit the future extension of New Orleans. Portions of each of these three parts ought to be 
applied immediately. The rest may be utilized as the expansion of the area of the city may 
demand it. 

First. The drainage of the city and the malarious marshes near it, and their irrigation after their 
desiccation. 

Second. Its protection against inundations from the lakes, and the improvement of Lake 
Pontchartrain for the objects of health, commerce, and pleasiu-e. 

Third. The prevention of the destruction of property by the shifting of the channel of the Missis- 
sippi Eiver, the undermining action of its current causing the submergence of its banks with all 
the superficial levees aud structures erected uj)on them, and the gaps and crevasses through which 
its waters at flood-tide rush in destructive torrents over the plantations of its valley. 

The whole cost of the drainage of ITew Orleans on both sides of the river by the Bonnet Carre 
. and Gretna aqueducts and their sewers will be less than $2,500,000, if the whole work is done 
honestly and faithfully. 

While I ask you to fix your minds upon the whole of this hydraulic plan, which ought to be 
executed as a loJiole, unmutilated by any work ui)on either of its parts which might mar its unity, 
I will now present a brief elaboration of its three separate portions. I can only gi^ e, without being 
tedious, its distinct and intelligible outlines, leaving the details of the work to be prepared by the 
engineers who will have the labor and honor of its mechanical execution. After mastering these 
outlines and the few new principles involved, and whose application is necessary for its successful 
completion, each part of it will be found so simple that but little genius or talent will be necessary 
to enable any honest and energetic engineer to execute the whole plan. 

I hope your minds will not be confused by a view of the magnitude and cost of this i^lan in its 
unity as it will ai^pear to the imagination. Only a part of it will be constructed at the expense of 
the city, which is the first part on drainage within the city by two canals with aqueducts. The 
pipes for drainage into these aqueducts necessary now ought to be laid as soon as possible ; but 
the most of them presented on the maps of the comjilete plan may be added sixccessively, year after 
year, as the future growth of New Orleans may demand their use. The drainage and desiccation 
of the marsh and swamp lands ought to be performed at the expense of the whole State of Louisiana, 
because she owns these overflowed and worthless bogs, and she alone ought to pay for their improve- 
ment. All the imi^rovemeuts suggested and explained in the second and third parts, and which 
refer to Lake Pontchartrain and the Mississippi Eiver, should be done by the Government of the 
United States, in which alone is vested the title of these public waterways of commerce. 

THE DRAINAGE OP THE CITY OF NEW ORLEANS AND ITS ENVIRONS, AND THE IRRIGATION OP 

THE RECLAIMED AND DESICCATED MARSHES. 

To make this complete, in view of its future extension, and to secure its health, and especially 
its exemption from diseases caused by local malaria, in its present condition, the drainage should 
include all its environs, embracing the i)eninsula of Algiers, aud all the area lying between the 
Mississippi Eiver and Lakes Maurepas, Pontchartrain, and Borgne, ^^ith their connecting waters, 
about 400 square miles in extent, as speedily as it can be applied. I recommend the construction of 



14 OONTEIBITTIONS TO THE 

a canal-aqueduct without locJcs, 30 feet wide, 27 feet deep, and 36 miles long, taken ont of the Missis- 
sippi Eiver at Bonnet Carr6 Bend, and turned into it again a short distance above the Noyes Canal 
near the upper curve of the English Turn ; and another of the same size, and 6^ miles long, across 
the neck of the peninsula of Algiers, from Gretna to a point below the English Turn, each outlet to 
enter the river at an angle less than 45° to the general direction. I suggest the depth of 27 feet in 
order that the bottom of the aqueduct may be below the beds of all the bayous, lagoons, and other 
stagnant waters and marsh-lands intended to be drained, and also that the mouths of the largest 
sewers may be covered entirely by the running water of the aqueduct. The water-level in the 
aqueduct must at all times be higher than the tops of the sewers in order that the suction by the 
attraction of cohesion of the fluid in the sewers by the larger volume of running water in the aque. 
ducts flowing at an angle of from ll|o to 45° in contact with their openings may be complete. The 
same rule must be observed where the sewerage is run into natural streams. Unless the proper 
angulation is observed the drainage will not be efficient. If the depth of 27 feet is not sufficient to 
cover the mouths of the large cylindrical sewers, the aqueducts must be made deeper, or the mouths 
of the sewers must be widened and flattened. The depth of the aqueducts must be measured, not 
from the natural surface, but from a line from the heads to the mouths drawn above the highest 
water-level of the river. For our present use, and for that of our successors for twenty years 23'>'oh' 
ably, these dimensions will be sufficient. In consideration of our financial depression, they may be 
constructed of wood, and they should not be used for any other purpose than that of drainage. 
They will last, and serve for that use only, and possibly be sufficient to accomplish the sanatory 
and other beneficial objects, for the fifth part of a century. But if before that brief peiiod shall 
elapse, the growth and necessity of the city shall requ.ire it, the whole aqueducts will be enlarged ; 
and others may be used for manufactories, irrigation, the supply of fire and other engines, and many 
other useful purposes. Various parallel aqueducts, separated from those made to convey the sew- 
erage of the city, may be drawn from the same inexhaustible source, and conducted to the same 
safe and ample outlet, and confined in walls of iron, glazed pottery, or other costly and permanent 
materials such as the necessities of 5,000,000 of people may demand, and which their wealth and 
taste will enable them to construct. 

With such a contingency as the necessity of future extension presented to us, in surveying the 
ground for our present humble work, provision should be made for the expansion which our more 
prosperous and powerful successors may give it. Therefore the breadth of an acre of land, or 210 
feet, on each side of the canals, for the whole length of their course, should be reserved uncumbered 
by buildings, and unfettered by any private or other legal rights which might prevent the enlarge - 
ment of the work to meet the demands of our multiplied posterity. 

The modest wooden structures proposed will be amply sufficient for our present wants, and will 
tax sufficiently our depleted resources. Between the two points on the river selected for the inlet and 
outlet of the canal for the left bank in which the wooden aqueduct is to be built, the distance by 
the mid-hanks channel of the serpentine course of the Mississippi is 46 miles. By the proposed canal 
the distance is only 36 miles. By this saving of ten miles the principle of the " cut-oft'" between 
bends, or greater fall and velocity of current, is secured. (See Plate IV, Diagrams 4, 5, and G.) 
The planking with which the aqueduct is to be lined will run parallel with its course to avoid fric- 
tion or any resistance to the rapid flow of the water. The bottom of the aqueduct must be dug entirely 
below the bottom of the Saint John Bayou, or that of the deepest tributary of the lakes which it will 
drain, and about eight feet below the lowest-water line of the Mississippi Eiver, during the most at- 
tenuated stage. It must be dug its whole distance below the lowest water-level of the river, and also 
somewhat below the surface of the lakes, in order that there may be always in it a depth of from 8 to 15 
feet of swiftly-running water. At proper intervals, about a quarter of a mile apart, spaces must be 
prepared and properly marked for the insertion in the sides and on a level with the bottom of the 
aqueduct of the main sewers. The size and number of these will depend upon the area necessary 
to be drained, and they can be constructed, and inserted successively as the necessity for their use 
shall arise. At least six of them are necessary now to drain the filth of the city and the contiguous 
marshes, and as many more should be constructed, to desiccate the swamps nearest to it, as its 
finances will permit. In order that they may perform their work well, all the pipes and sewers 



SOIEI^OE OF HYDEAULIC EKGINEEEING. 15 

must be made to enter the canals and eacli other at angles of from lljo to 45° tvith the direction of 
the course and current of the water. A greater angle than 45° will ijrevent their most efficient 
action. The main sewers should rest npon the bottom of the aqueduct, and their inner rims must 
be shaped to fit the inner surface of it ; but no parts of the pipes or sewer-ends should fail to reach 
the inside surface touched by the water of the bottom current, and they should not project into it. 
If properly constructed the ehmuzesis will be complete. The bottom current of the larger body of 
water in the aqueduct passing rapidly by the mouths of the sewers, hy the attraction of cohesion will 
sucli otit all the fluid they convey in contact with it. I recommend that the mouths of all these 
sewers be made of pottery, glazed on the inside, and crooked and shaped at the proper angle for 
insertion at the time they are moulded. All of their larger sections shou.ld be made of the same 
material. 

The openings in these sections should all be angulated on the same principle, as we are taught by 
the venous circulation of our blood, which is the reverse of that of the arterial. The contraction of 
the heart propels the blood through the great arteries into the smaller, and diffuses it by propulsion 
throughout the body and into the little veins ; but it is returned by them to the heart by suction. The 
little veins run into the greater at various angles, and discharge their blood into the vence cavce, or 
larger sanguiducts, which finally pour it into the right auricle of the heart. I liope this princi]>le 
and this rule of angulation will be observed in the construction of the entire sewerage and drainage 
of this city, and in the course of time of the whole Delta and of all other swampy areas. The bot- 
toms of the canals should be cut low to give all the sewers and the smaller pijies a sufficient fall, 
which ought to be carefully observed by the engineers who place them in position. Perpendicular 
tubes may be dropj^ed into them from all necessary points and covered by grating or sieves of iron 
to strain the trash and drain the surface rain-water into the canals. But in the construction of all 
the underground sewerage the principle of the vena cava should be observed. This is elanuzesis, 
and if it shall be wisely followed every particle of the noxious and offensive filth of this city will be 
easily and harmlessly discharged by the aqueducts into our grand vena cava, "the Father of Waters," 
which will pour it itito the abyss of the great lieart of our commerce — the Mexican Gi-ulf. 

Our language is already so overburdened with useless words, many of them synonyms, while the 
most of them are insignificant, and the Avhole worthless addition to our mother tongue mainly the 
work of shallow-minded pedants who make it year after year more difficult to be read, spoken, or 
understood, that an apology is due to the whole world by the man who ventures to give a new word 
to our cumbrous dictionary. ETcmuzesis is the only word I ever coined. I invented it, not because it 
is a thundering Greek derivative, from ek, out of, and muzeo, to suck, which in a scientific controversy, 
and especially in a metaphysical contest such as theological disputants sometimes wage furiously, 
is said to be worth a thousand arguments, but for the reason that I could find no word in our lan- 
guage which properly designates the application of the principle of nature by which fluids flowing 
in large channels, by the attraction of cohesion suck out and blend with their currents those which 
are brought into contact with them through smaller ducts. The phrase '■'•sucTcing ouf is rather 
rough and awkward, and I therefore prefer my sole coinage, and only offense to my native language, 
ekmuzesis, which expresses the idea as well; but for the use of which I beg pardon of all who read, 
write, or speak it. 

I am afraid, while I describe the beautiful invention of elcmuzesis, that you may overlook the 
important fact that the efficiency of the i)lan of drainage I recommend does not depend upon the 
successful application of this useful scientific discovery. The whole plan of drainage was elaborated 
before I made it. The leading idea of the whole plan is to drain the noxious fluids of the city and 
the contiguous marsh-lands into dee]) canals enclosing well-constructed aqueducts to prevent these cut-offs, 
which loill he shorter and swifter than the river curving around the hends, from enlarging and making 
new river-beds. These deep aqueducts are to he taken out of the deep current of the river and turned 
again into its depths hy a shorter route than the natural serpentine course of its waters; and all the 
mouths of the sewers intended for loiv marsh-drainage mtist descend to the level of the hottom currents of 
these canals, which they must he made to reach hy properly graduated falls. 

In every instance the mouth of the sewer must be entirely covered by the water in the aqueduct, 
bayou, or river into which it enters, in order that the cohesion of the fluids and the suction of the 



16 CONTEIBUTIONS TO THE 

4 

smaller by tlie larger body in motion may be complete. The larger body will always draw the 
smaller along with it if the discharging-pipes or sewers are angulated properly from 11^° to less 
than 45°. At less or greater angles they will work badly or not at all. 

There, at their points of contact with the aqueducts, their contents must be discharged into 
them either by elcmuzesis or by some other mechanical contrivance. 

It was while seeking for the simplest, the most efficient, and above all other considerations the 
cheapest device, that T made the discovery of elcmuzesis. I had studied the plans of various draming- 
machines aud steam-pumps for transferring the contents of our vile cesspools, Augean stables, and 
chartered Stygian and death-dealing canals into a purifying aqueduct of living and life-saving water ; 
and after revolving in my mind the Tcnoion and many untried loindmills and steam-drainers, I found 
them all either too expensive, or unreliable contrivances which would not work\luring the raging 
of a cyclone, when a deluge is falling from the sky, and when Pontchartrain, lashed into fury by 
the wings of the temjiest, threatens to overwhelm the city with its waves. When we want these 
tricky servants, especially our draining-canals and draining-machines, to work the hardest and fastest 
to save us, the steamers stop work or desert their posts in despair, and the canals "join the enemy," 
and swell the forces of the invading flood. They, and all the devices hitherto used, seemed to my 
mind as imi)otent to protect us against the combined powers of the typhoons and lakes as the 
much-used and much-abused hroom of the sage Dame Partington to sweei) the swelling Atlantic 
trom her cottage floor. I then invented a simple water-wheel to be revolved by the current of the 
canal, and which would work a powerful pump by night and day, and in a tempest as well as in 
the calmest weather — a cheap wooden contrivance, which would only require one hand to grease 
it and keep it in order, and which would j)erform its labor even without grease or any attendance, 
and work the hardest and fastest when the water is the highest. Six of these inexpensive machines, 
which consume nothing, and which are almost self-acting and self-suj)i)orting, stationed at the 
mouths of the main sewers, a quarter of a mile apart, to discharge their contents, are cheap enough 
for any reasonably economical plan of drainage ; and I cordially recommend them to all those who 
cannot grasi) a new idea and who cannot comprehend the utility of a new device until some bolder 
spirit uses it successfully. 

Here with these water-wheels, simple as the flutter-mills made by little mountain boys, and 
placed upon the rills of their native glens, I might have closed my drainage plan. But in view 
of the diminished resources of our city and State I concluded to devise something even cheaper 
than my little "flutter- wheels"; and as you know that "necessity is the mother of invention," I can 
say with truth that the poverty of jSTew Orleans, and the stern necessity tor rigid economy which 
oppresses our whole State, is the mother of elcmuzesis. 

IKRIGATION. 

(See Plate IV, Diagram 4.) 

It is easy to see how the same aqueducts constructed for drainage may be used for irrigating 
the bogs aud marsh-lands they desiccate. The Mississippi, and the bayous leading from it, like 
the Atchafalaya, Lafourche, and others ; and its great affluents, like the Eed and Arkansas, and 
all the smaller tributaries, during their periods of flood have their water-levels high above the sur- 
faces of the cultivated fields which they intersect. If these fields lie near their banks, and if their 
channels are prevented from shifting by jetties properly angulated to give permanency to their beds, 
the sewers and subsoil ditches may be conducted at proper angles directly into their deep bottom 
currents. I only recommend the use of aqueducts where the swamps to be drained are remote from 
the running rivers and bayous or where these streams are unrestrained and shift their banks, and 
in their unbridled condition would fill the sewer-mouths with mud or wash them away. But 
superficial irrigating-ditches should be run directly above the subsoil drainers into the plats of ground 
needing irrigation during the droughts of May and June, when the flood is at its height. When 
the water they convey from the top currents to the fields and gardens has irrigated them sufficiently, 
through openings into the sewers it can all be returned by elcmuzesis into the aqueducts ; and all the 
expense of draining-machines may be obviated. 



SCIENCE OF HYDEUALIC EN^GKfEEEING. 17 

This plan is so simple, and will effect tlie drainage of all the marsh-lands of onr State so 
cheaply, and render them so exceedingly valnable, that it is the duty of our representatives to stop 
their sale immediately at the low price now fixed as their value, and use the whole valuable and 
easily reclaimable area to pay our State debt, and at no distant day to so lease them as to provide 
for the expense of the State government and the suppoit of our schools, and at the same time to 
exeinpt the ijeople of Louisiana from all State taxation. 

That this is entirely practicable is made evident by the following facts; There are 9,500 square 
miles of overflowed lands, nearly all of which belong to the State of Louisiana. Of this area 5,200 
square miles are sea-marshes and trembling prairies overflowed by salt water during storms on 
the Gulf. Much of this area can be reclaimed by ekimizesis where the deep river and its outlets 
run near it into the Gulf. The rest can only be reclaimed by the means used by the Dutch, or 
appliances similar to those by which that energetic nation has conquered so large a portion of Hol- 
land from the sea. But the State owns about 4,300 square miles of fresh- water, wooded swamps, 
easily drained. Four hundred square miles of this State land lie near this city and its immediate 
commercial waterways. Each acre, of the 250,000 acres, if reclaimed, would produce fi'om one to 
three hogsheads of sugar. Even if the whole were sold for only $100 iier acre it would yield 
$25,000,000, and double the amount of the State debt, which is about $12,500,000. The rest of 
the 3,900 square miles could certainly be leased on such terms as to exempt our j)eople from all 
taxation. 

Areas of these overflowed lands can be successively drained by the State and brought into the 
market as the necessity for raising funds to endow a system of State education, or to replenish the 
State treasury for any i)uri)ose whatever, may arise. An act of the legislature should be promptly 
-passed ]}rohiMti7ig their sale at present. If it is not, as soon as capitalists discover how easily and 
cheaply they can be drained, individuals and laud-rings will be apt to secure them; and they will 
be bought for pur])oses of speculation, and our posterity will be deprived of their incalculable 
benefits. Such reckless, goJden-egg-goose-ripiymg legialaiioii has clmracterized our State and Federal 
Governments since their origin. A greater wrong to our descendants could scarcely be conceived 
by selfish and cunning covetousness, or be perpetrated by cold-hearted stupidity and corruption 
combined. The only argument for its continued criminality is that these lands are worthless as 
they are, and that it is better to sell them to private individuals and let them be cultivated in rice, 
sugar, cotton, and fruit, or to be used as improved pastures for flocks and herds, than to lie idle as 
reed-marshes aud cypress-swamps. This is not so. Much of our marsh-lands is owned by wealthy 
corporations and private individuals. Their successful ex])erimeuts in draining them by this 
method, or those made by the State, will n)ake all such lands, whether public or private, lise in 
value. Let speculators buy and sell their own. The State should be in no haste to rob the future, 
and to squander the inheritance of her children. But it is said that our legislators cannot be ]}re- 
vented from passing such disastrous laws. If this is true then we have reached the nadir of corrup- 
tion, and cannot find wise and virtuous representatives to make our laws. We do not deserve to 
be land-owners, or freemen; and are too stupid and corrupt to govern ourselves, which I am 
unwilling yet to believe. 

When I reflect how the problem of subsistence for the multiplying millions of our race has per- 
j)lexed wise and benevolent political economists, who have not been able to devise any i^rovision for 
employing and feeding the vast multitudes of India, China, and other densely-peopled countries as 
they will inevitably increase in the near future without the iutervention of tlie destructive agencies 
of pestilence and war, and how it is solved, by this discovery^ I am overwhelmed with wonder and 
gratitude in view of the grandeur of the beneficent results which will flow from its certain application. 
The impoverished myriads of the inhabitants of the marshy valleys of the Yanktsekiaug, Hoang-ho, 
Cambodia, Ganges, and Indus will not perish nor migrate for the want of lands to cultivate. Every 
untillable and uninhabitable bog and jungle can be I'cclaimed and transformed into the most prolific 
soil, to furnish abundant food for ten times the number of peoi^le who now live upon their alluvium. 
Every quagmire of the Danube, the Po, the Amazon, the Orinoco, and their tributaries, and all the 
great riveis of Africa, in the course of time will be dried and sanified by it. There is not a marshy 
region of the earth through which a canal of running water can be carried which will not be reclaimed 
3 H E 



18 CONTEIBUTIONS, ETC. 

by it when the wants of a dense population shall demand it. The same aqueducts for draining 
and drying the marsh-lands will also be used in periods of drought for tlieir irrigation. Ordinary 
ditches, leading from them when they are full of water, or simple water-wheels when their currents 
are below the levels of the fields, orchards, and gardens, will supply them with moisture when rain 
is wanted ; and all the wasted water will be returned into the aqueducts by ekmuzesis. 

This system of drainage and irrigation by the same simple contrivances will give a healthy 
and ample circulation of water to every river-valley independent -of any supply from the clouds, 
and even enrich the sands of Sahara, and the great deserts of Asia and America, and all the sterile 
regions intersected by such rivers as the Nile, the Rio Grande, and the Colorado of the Great Basin. 
It will work as efficiently to nourish and cleanse the soil of our mother earth as the circulation of 
the blood by the arteries and veins supplies the human body with fluid, and i^urities it from its 
stagnated and unhealthy excess. I know that we cannot fix any limit to the inventive power of the 
human mind, and I dare not assert that a better plan of diainage and irrigation may not be invented 
by some genius to whom the future may give birth, but I will say that no mode so simple, cheap, 
practical, and effective has yet been i)lanned in the present era or in past ages; and I cannot con- 
ceive how it can be improved in any future period of time, unless a better plan for the circulation 
of the blood can be discovered than that which Eternal Wisdom has created, and of which this 
hydraulic system is an humble human imitation. It is but a copy of "nature's model," and the 
aijplication of nature's hydraulic system — the wisest and best, because it is the work of God alone, 
whom it is our duty to worship and imitate. 

This plan will drain every lake, swamp, or marsh intersected by an aqueduct, or by a river or 
running bayou whose bottom current is lower than the bed of such shallow waters and marsh-lands 
as need desiccation. By the same cheap and simple method all such spots may be irrigated after 
drainage without the aid of machinery, by surface ditches, when the water in the aqueducts or nat- 
ural streams are filled by the spring rains, and flow with surface-levels above those of the lands 
near them. All the alluvial lands of the Mississi])pi, and other rivers with which I am, acquainted, 
answer these conditions, and need these improvements. There are no cities whose plans of drainage 
may not be greatly improved by the proper application of these principles, and especially the 
elimuzesis dependent upon the proper angulation of sewers and draining-pipes. 

When it is necessary to drain swamjjs into bays like the Delaware and Chesaj)eake, which have 
tides, and which have to be utilized in consequence of the impossibility of making the culverts or 
sewers reach the direct onward flowing ocean currents, as represented by Diagram 3, Plate VII, the 
drainage must be effected by forking the outlets of them as in Diagram 4, Plate VII. 

The Tiber Creek and other sewers might be made on this principle to drain the flats of Wash- 
ington City into the Potomac. While the general direction of the sewer near its mouth should be 
at right angles to the course of the river, it should be forked into divisions each of the same size, 
and equal in capacity to the main sewer. They should enter the bottom currents of the river at 
angles of about 22^°, and be at all times covered by the water of the river, so as to expose the 
two diverged mouths alternately to the suction of the ebbing and flowing tide. When the tide is 
flowing up the river the mouth («) will be idle, but the mouth (ft) will receive the ekmuzesis of the 
ascending tide and pour the contents of the sewer into it. When it ebbs this upj)er mouth [h) will 
be calm, and the lower mouth (a) will be sucked by the outflow., and discharge vigorously its filthy 
waters into the ocean-bound river. (See Diagram 4, Plate V.) 

This plan may be applied successfully to the drainage of the Kidwell flats, and all marsh- 
lands situated ui)on tide water creeks, inlets, gulfs, and bays. But their tidal currents nuistbe first 
utilized so as to give fixedness to the channel-beds and permanency to the shores by the applica- 
tion of the method for utilizing ebbing and flowing or tidal currents, illustrated by Diagram 9, 
Plate III. 

The mouths of the sewers must always be covered by the water into which they discharge their 
contents, in order that they may receive the full force of the suction of the attraction of cohesion, 
and also to iirevent their mephitic matter from tainting the air. 



:pjle.t II. 



THE PHYSICAL HISTORY AND GEOGRAPHY 



OF 



LAKE PONTCHARTRAIN. 



AND 



ITS CONNECTIONS WITH THE MISSISSIPPI RIVER AND THE GULF OF MEXICO: 



WITH A PLAN FOR ITS IMPEOVEMENT, INCLUDING A METHOD FOR THE CONSTRUCTION OF CHEAP 

AND PERMANENT BREAKWATERS FOE THE PROTECTION OF HARBORS WHOSE BEDS 

ARE SAND, CLAY, AND OTHER FRIABLE MATERIALS. 



PART II. 

THE IMPROVEMENT OF LAKE PONTCHARTRAIN. 



The health aud commercial i)rosperity of all the Delta of Louisiana, north of the Mississippi 
River, and below Baton Eouge, de])end upon the reopening of Bayou Manchac. The deepening of 
the two entrances to the Gulf, Chef Menteur and the Eigolets, and a lake harbor, all deep enough 
to admit ocean vessels of a large draught through the Mississippi Sound to l^ew Orleans and to 
Baton Eouge, can only be effected by the improvements planned in this essay for this bayou and 
Lakes Mauiepas aud Pontchartrain. The overflows of the lower coast and of the whole Delta 
"will be prevented if a pi'0]>er system of levees, protected by angiilated jetties connected with them, 
is applied — the jetties always to be constructed above the caving banks to deflect tlie bottom cur- 
rent of the river from them, and to deposit batture against them. Without these imiirovemeuts 
for this bayou and these lakes and their outlets, no plan for the sanatory and commercial welfare of 
New Orleans will be complete. The cost of the whole plan will be less than $1,000,000. 

This beaatiful lake, although it lies within the limits of the State of Louisiana, is, I suppose, 
the property of the United States by the same title which gives it the ownership of the Mississippi 
Eiver. The cession of Louisiana to the United States by France conveyed with it this great river 
and all its navigable tributaries, and the lakes connected with it and the Gulf of Mexico, which 
are waterways of commerce. These "public highways" and commercial avenues, in which all the 
people of the United States are interested, have never been relinquished by the General Govern- 
ment to this State. As the ownership of this lake and its connections with the great river and the 
sea is vested in the United States, it is the duty of its Congress, for the "general welfare" of the 
people, to make all tlie improvements which the necessities of commerce and other objects of public 
utility require. National justice demands that this should be done for this river and lake, and for 
all the avenues of travel and traffic leading to New Orleans, with the same liberality and for the 
same objects as appropriations of the public money have been made for the improvement of the 
harbors of Boston and New York. Even if the city of New Orleans or the State of Louisiana 
were in a condition to undertake the work of hydraulic engineering necessary to be applied, and 
which our highest interests so urgently demand, the consent of the Government of the United 
States through an act of Congress would have to be obtained. Even in the application of the plan 
of drainage which I have recommended, and which the health aud commercial prosperity of New 
Orleans require the city to execute immediately, sucli an act of Congress may have to be obtained. 
To make the drainage of it effective, the Bayou Saint John and the caaals and basins of stagnant 
water should be drained. 

I have been informed by some of our most eminent lawyers that the right of property in the 
Bayou Saint John is clearly vested in the United States. At the period of the purchase of Louis- 
iana from France this bayou was an important commercial waterway ; and wlien New Orleans was 
a fortified "\illage it was considered indispensable to its prosperitj^, but now that it has grown to 
be a great city, it has become a nuisance and an offensive generator of malaria. If an act of Con- 
gress is necessary it ought to be obtained immediately, in order that this stinking cesspool may be 
drained and dried as soon as jjossible, and its bed transformed into Streets and lots for buildings 
and gardens. All the other receptacles of filth aud putrid water, the canals and basins within the 
city and its environs, ought to be destroyed and their commerce transferred to the shore of the 
lake aud to the lines of railroads terminating at its wharves. The city authorities should lose no 



22 CONTRIBUTIONS TO THE 

time ill abating these niiisauces, "which are the principal causes of our epidemics and malarial dis- 
eases, and, as such, the main hindrances to the growth and prosperity of this metropolis. K our 
representatives in Congress will do tlieir duty, it will not be impossible, or even dififlcnlt, to get 
tlie General Government, of which as the representatives of the people of Louisiana they form a 
part, to make all the appropriations of money necessary to improve I ake Pontchartrain and its 
necessary connections with the Mississippi River and the Gulf. It is certainly the duty of the 
United States to do this. 

THE IMPROVEMENT OF LAKE PONTCHARTRAIN. 

In 1814 this lake received a very large su]:>ply of fresh water directly from the Mississippi 
River through the Bayou Manchac. This bayou left the river opposite Manchac Point, about 12 
miles below Baton Rouge, and after coursing along near the high and beautiful hills which are the 
escarpments of the fertile alluvial "bluff-formation," ujjon the plateau of which are built Natchez, 
Vicksburg, Memphis, and other fine cities, it discharged its muddy waters into Lake Maui'epas, 
distant from its head on the Mississi])pi on an air-line about 32 miles. But it reached its moutli in 
this lovely lake after meandering at least a hundred miles through recently formed alluvial lands 
of inexhaustible fertility, and near tlie more elevated plateau of the bhift'-formation crowned with 
grand primeval forests of beech, inagnolia, and all the finest trees of the southern woods, and 
dotted with the multiplying settlements of thrifty planters. On its course it received the waters 
of the pure and bold Amite, which rises in the pine forests growing upon the barren sands and 
pebbles of the glacial drift which supports all the vast pitch or long- leafed pine woods of the South, 
which peculiar soil of variable depth overlies all the lower surface-depressions of the tertiary, and 
furnishes the exclusive food of this valuable tree, which does not grow indigenously upon the ter- 
tiary, or any older formation which " croi^s out" through this diluvial "orange sand" deposit. 
This water-worn and discolored detritus of the post-tertiary glacial flood w^hich poured over North 
America from the Arctic Ocean is widely strown over all the Gulf States, and covers all the 
upland areas of Mississippi, Louisiana, Alabama, and parts of Texas, Arkansas, VVe«it Tennessee, 
and Florida, no matter what may be the denuded formations lying immediatelj^ beneath it. But it 
is the general surface of the tertiary formation of the Gulf States, and the only land uijon which 
the forests of the long-leafed pine are found. The Amite and its numerous tributaries flow out of 
these pine lands and through the far more fertile blufi-forination ui)on which no long-leafed or 
other pine grows spontaneously. This is a recent deposit which overlies the glacial drift. It was 
formed by a local deluge or the drainage of one of those post-glacial seas, such as existed upon all 
the continents, and were drained in a subsequent epoch, and either synchronously or successively 
in times not very distant from our present era. The particular fresh -water sea, whose drainage 
foi-med the Delta of Louisiana and much of the flat coast-lands of Texas, and all the bluft'-forma- 
tion of the States of the valley south of the Ohio River, existed between the Rocky Mountains 
and the Appalachian chains, and the older connected and denuded sedimentary rocks of the Ozark 
and Cumberland, which before their disruption and severance formed the southern shore of this 
mediterranean sea, whose northern limits, penetrated by the McKenzie and other Arctic rivers, 
have not been explored. It was certainly drained by the Mississippi River, which, after tumbling 
for ages over a great water-fall above Cairo, whose marks are seen uj^ou the lofty cliffs on both 
banks, cut its way up towards the upper part of the rim of this great sea by a process of erosion 
similar to that by which the Niagara is trenching its chasm towards the depths of Lake Erie at 
Buffalo, where its falls will inevitably disappear, and with them Lake Erie will also vanish and 
destroy Lake Ontario, and transform the Gulf of Saint Lawrence into a delta, and exhibit all the 
phenomena on a smaller scale displayed in the Mississippi Valley when the great sea, whose 
remains are the lakes Superior and others left in the deepest depressions of its bed, poured its waters 
and their wrecks into the Gulf of Mexico at Baton Rouge, and formed the vast area of the coast- 
lands and swami)s of Louisiana, and the high plateau of alluvial bluffs, crowned with rich plan- 
tations and magnolia forests. 

But this digression is more suitable to a geological dissertation than to an essay on hydraulic 
engineering for the improvement of Lake Pontchartrain. I would not have made it if it were not 



SCIENCE OF HYDEAULIC EI^Gi:NEERmG. 23 

written to be read by members of Academies of Sciences, as mcII as by illiterate eiigiueers and poli- 
ticians. I will say no more in regard to the physical geography of this lake and its principal 
affluents through Lake Maurepas, except that these lalics and Bayou Manchac are the shrunken remains 
of the most eastern and northern mouth of the many mouths of this mediterranean-sea river when it 
ilowed in the zenith of its grandeur, and entered the Gulf from the Sabine to Pearl Eiver by hun- 
dreds of embouchures, some of tliem wide as Vermillion and Barrataria Bays, and the whole volume 
of fresh but" angry water, a hundred miles wide and 000 feet deep, rushing froui Cairo to the sea, 
presented the appalling spectacle of a river compared with whose gigantic size and strength the 
magnificent Amazon in the periods of its grandest floods is but a pigmy rivulet. In 1814, ages 
after the drainage of this sea had been effected through these great mouths, and such climatic 
changes had occvirred that the mammoths and many of their pachydermatous associates died, the 
Mississippi pined and Avithered away, until it could no longer fill its great southern mouths, and 
preserve the vast delta it had thrust into the Gidf a huiulred miles beyond the present shore of 
Louisiana. It at length became too feeble to for(!e its way into the Vernnllion, and the other mouths 
it had made in the days of its manhood's prime when it filled uj) the whole alluvial area Avith logs, 
brush, sand, and mud, and all the materials of the lands its deluge had engulfed from the mediter- 
ranean sea to the ocean. It could not flow in its feebleness through these wood-bound barriers 
which it had buried, in the plenitude of its strength, sevei'al hundred feet deep. It was compelled to 
leave its direct southeru course fiom the pole to the ecpiator, at Baton Rouge, and flow through its 
northeastern mouths carved through the yielding tertiary sands and marly clays. Only a few 
little remnants of its ancient channels, much obstructed by logs and buried wrecks of all kinds, 
were occupied by the Atchafalaya and smaller bayous leading from its right bank to the remnants of 
its mouths in the Gulf, where all its delta has long been abandoned to the erosiA'e action of the tropi- 
cal Gulf-Stream current, which has swept away more than half of its original formation, and low- 
ered the Mississippi to its ])resent level. 

It is now faintly and vainly struggling to extend its alluvium far out of its normal direction to the 
east. In 1814 Bayou Manchac was the sole representative of its ancient northeastern outlet. It was 
then and is now a very necessary carrier for the products of the fertile "bluif " plantations at whose 
base it flows, receiving the Amite which intersects the prolific plateau; and it is also much needed 
for the commerce of the rich alluvial lauds which for a hundred miles line its banks. When Gen- 
eral Jackson came from Tennessee, in December, 1814, to defend ITew Orleans against the formidable 
force sent by Great Britain to ca]>ture it, and to conquer and hold with it the whole valley of the 
Mississippi to connect it with her West Indian and Canadian possessions, he found Bayou Manchac a 
deep and broad navigable stream, which the British had thoroughly sounded, and through wiiich they 
had determined to pass gunboats drawing from 7 to 12 feet water, to cut oft' his supplies from Kentucky 
and Tennessee, and attack him in the rear, and closely besiege him, encircled in the city by their naval 
and land forces without the possibility of his relief. This wonderful man had never, heard anything 
about Je^/ies, mattresses, or caissons. I doubt whether he understood the definition of a dozen technical 
terms of military or civil engineering, and I am sure that he knew nothing that any books could 
have taught of hjdraulics. Such things had not penetrated the pine woods of the Carolinas, nor 
the wild woods and canebrakes of Tennessee and the Creek Nation, where he had spent his life 
before he came to defend this recently-formed semi-aquatic spot of earth against the most thoroughly 
educated and the bi'avest and best disciplined troops in the Old World, and who had just conquered 
the Old World's conqueror. He had read no books on hydraulic engineering. He needed no infor- 
mation which they could give him. He had seen axes fell trees, and he had seen the beavers cut them 
down with their teeth, and make dams with them which would guide the course of rivers, or obstruct 
their channels entirely with scientific works which no floods could remove. He had the divine gift of 
genius, and the rare but invaluable talent of conuuon sense, and with the faculty to learn from 
observation and experience, and guided by the unerring instinct of the beavers, the i)erfect hydriiulic 
engineers of the God of nature, Ire blockaded Bayou ]\Ianchac witli trees and heaver brush-work so 
effectually that he rendered it useless to the British, and, unfortunately, to the planters and mer- 
chants also. In fact he almost obliterated that mouth of the old Mississippi from the face of the 
earth. By his original feat of hydraulic engineering he rendered abortive the British naval victory 
on the lake, and he saved New Orleans; but the effect of his successful work has been for sixty- 



24 CONTRIBUTIONS TO THE 

three years most injurious to the commerce and health of the resicleuts near the bayou and its tribu- 
taries, and around the shores of Lakes Maurepas and Pontchartraiii, and it has been ^ery detri- 
mental to the city of New Orleans. 

Before General Jackson closed it, a large volume of fresh running water was discharged by it 
into Lake Pontchartrain. This had been thoroughly clarified by its passage through Lake Maure- 
pas. After winding around Jones's Island it flowed into Lake Pontchaitrain at the Cli0(;taw Vil- 
lage by a single mouth. The volume of pure water from it so filled the lake that it gave it a strong- 
current toward the east along its shores, quickening the currents of the Tangipahoa and Tchefinuitce 
Rivers, and of the navigable Bayous Lacombe, Viiu-enc, Saint John, and all the smaller streams emp- 
tying into it ; and at the same time, while adding to the health of its shores by improving their nat- 
ural drainage, it deepened the outlets of the lake to the Gulf through the passes Chef Mentenr and 
the Rigolets. 

The first improvement 1 would suggest for Lake Pontchartraiu is, to reo^je?i Bayou Manchac, 
and to utilize it for inigatiou, drainage, navigation, and all the beneficent uses to which run- 
ning water can be ai)plied. As it was closed by the United States, whose power was skillfully 
but arbitrarily wielded by the greatest of its generals, the damage of more than half of a century, 
and which it is difficult to estimate, ought to be promptly and liberally repaired at its cost. 

The next improvement I recommend is to utilize the Bonnet Carre crevasse. 

The cause of the opening of this crevasse was the closing of the Bayou Mancliac. Whenever a 
natural outlet for the relief of the flood water of the Mississippi is closed, the overburdened volume 
will relieve itself by a crevasse whicb it will burst through some weak point in its })atural or arti- 
ficial banks. It generally selects some caving bend the nearest to the outlet or mouth of the chan- 
nel which has been rashly closed in oi)i)Osition to the law of its natural hydraulic system, and which 
the wisdom of the ancient aboriginal mound-builders and agriculturists of its valley taught them 
to regard with sacred veneration. Instead of closing these safety-valves for the escape of the flood- 
waters., in order to %'A\q themsehes from inundation, as some thoughtless engineers advise us to 
do in regard to the Atchafalaya, Lafourche, Plaquemines, Yazoo Pass, and others, they carefully 
oi)ened them all, as did the ancient Egyptians to control and utilize the floods of the Nile. Acting 
upon the hints which bountiful Nature had given them, and guided by its' wise and beneficent dij-ec- 
tions, they not only enlai'ged, deepened, guided, and carefully leveed all these natural outlets, but 
constructed many others for the various useful i)urposes of imA'igation, drainage, and irrigation. 
No physical geograi)her with oidinary capacity for ()bser\'ation can doubt this who will carefully 
examine the vast net-work of bayous counecting the Mississippi and the Yazoo, and see the pow- 
erful levees they built yet standing covered with the tuuiuli and all the remains of the extinct 
millions of this enlightened but vanished race, abundant as those which were constructed by the 
subjects of the ancient Phai'aohs, and which gave to the Yazoo Ok-Hinna, its Indian nanu^, which 
in the languages of the (Jhoctaws and Chickasaws means " the River of Ruins." 

The connections of the White, Saint Francis, Washita, and Red Rivers with the great liiver and 
the Gulf all prove the same instructive theory to be correct. The Nile was once an unbridled and 
shifting river, which, from the cataract of Syene to its mouths in the Mediterranean Sea, flowed 
through swamps, natural bayous, and lakes, and overflowed them all, until Menes and other wise 
uionarchs bridled and controlled its waters with canals, aqueducts, and leveed lakes, natural and 
artificial, in the manner described by Herodotus. All these were used for three pur[)oses — the 
pi'e\ention of overflows, di'ainage and irrigation, and navigation. When the Nile was dangerously 
full, and the land was threatened by it with a flood, after impressive ceremonies, some of which are 
yet observed and conducted by the modern rulers of Egypt, the water-gates at the head of each 
canal were opened, and the fields were all irrigated, and the dangerous water was made proi)itious 
to The soil, and then i^ermitted to flow by many outlets to the sea. Lake Mceris. 30 miles long 
and G miles wide, leveed and guarded by watei'-gates placed ui)on all the inlets and outlets of the 
great aqueducts connecting it with the Nile and the sea, was filled'. When the flood had spent its 
force, and the work of irrigation was accomplished, the gates were closed, and the water of this 
and all the other lakes and artificial reservoirs was retained and held at a level high above that of 
the valley fields, to furnish any deficiency of water for irrigation the next year, if the annual rise of 
the river was not sufficient to supply the wants of agriculture. 



SCIENCE OF HYDKAULIC ENGINEERING. 25 

I therefore object to the theory of closing- the bayous, for these uiiaiiswerable reasons : First, 
they are necessary for the inland commerce of the valley, becanse they fnrnish the cheaper means 
of transportation; second, they afford the best and only means for draining and desiccating, and then 
for irrigating all of its swamp lands remote from the Mississippi ; third and finally, they may be made 
to save the valley from overflow, as tlie opening of the Bonnet Carre and other crevasses and the 
bursting of the Ic'ees of the upper coast saved New Orleans from the May flood of 1874. Onv true 
policy is to jetty the main river with converging brush and crib work to give fixedness to its chan- 
nel and deepen it by erosion, and to open every outlet and utilize it for commerce and agriculture. 

Instead of closing Bonnet Carre crevasse, I think a ship canal ought to be made of it about 8 
miles long and 200 feet wide, witli a depth of feet below the lowest water-level of the Mi8sissi])pi, 
and it should be run upon an air-line due north into the southern margin of Lake Maurepas. It 
should be properly shielded and guided with jetties at its outlet from the Missi.-sippi to prevent it 
from enlarging its channel, and also at its entrance iiirto the lake to hinder the formatiou of a bar. 
This canal cun be used for navigation and the drainage and subsequent irrigation of 64 square 
miles of marsh-lands adjacent to it, now worthless for agriculture, but which it will make equal in 
fertility and value to any in tlie State. The large accessiou of water which tliis Bonnet Carre Canal 
and the reo])ened Bayou "Manchac will give to Maurepas will make a strong current in this lake to 
the east and through the Jones's Island Pass into Lake Pontchartrain, and through it into the Gulf. 
The (;urrent will be a continuation of that of Bayou Manchac, which, although it will be swift and 
deep, will be easily controlled by jetties of i)iles and fascines of felted brush. There will be but 
little current in the canal, as there would be if its course wei'e south or even east, and it will need 
no lock. 

Many years ago I discovered, and ten years since I demonstrated in a lecture to the New 
Orleans Academy of Sciences, that the cause of the velocity of the current of the Mississippi was not 
its/«/?, but its course from north to south; or the centrifugal force which it receives from the eartWs 
revolutiDH upon its axis ; and which force propels all fluids upon its surface from the poles towards 
the equator, and retards their centripetal flow from the equator towards the poles. It is this force 
which makes the earth an oblate spheroid instead of a sphere. It causes its equatorial diameter to 
be about 27 miles longer than the polar. It elevates the tropical oceans under the equator 13^- 
miles above a globe level. It causes the cold centrifugal ocean ciu-reTits to flow out from the poles 
towaixls the equator, side by side in the temperate zones, but opposite to the Gulf Stream, the Kuro 
Siwoo, and other centrifugal currents which rise in the torrid zone above them, and seek their leve' 
by running to the poles, where they are metamorphosed and merged with them by the cold of the 
frigid zones. This force, which retards the currents of the La Plata ami the Nile, whose course is 
directly oppisite to that of the Mississippi, and which flow/Vow the equator tounirds the poles, will act 
directly against the current of the Bonnet Carre Canal, and give it a gentle descent into Lake 
Mauiepas. 

The third improvement I recommend for Lake Pontchartrain is a jetty of piles and felted 
fascines at the mouth of the pass at the Choctaw Village. This should be shaped like a \/, with the 
point meeting and dividing the combined waters of Lake Maurepas, and directing their currents 
around the shores of Lake Pontchartrain to its two passes into the Gulf. The effect will be to foi-m 
a large, beautiful, and i)erfectly healthy island at the upper end of the lake, upon which a star-fort 
can be erected to guard this important inlet. Hotels, hospitals, and buildings of all kinds can be 
built upon its healthy and airy site. It will enlarge its area slowly and continually, while the cur- 
rents eddy around it, and deepen near the shores. These currents should be utilized for harbors a 
half mile wide, mads by br^ikwaters of piles and brash fascines a h ilf mile from the lake shore and 
parallel with it. The materials (Iredged to deei>en them next to the shore, for the convenience of 
wharves and the motions of vessels ot all kinds, should be used to (joustruct a high and broad 
levee to protect the city and i)lautatious from the storais of the lake. Intervals at least 200 feet 
wide ought to be left in the construction of the breakwater, at distances of two miles, for the passage 
of vessels. This bre.ikwater, h.ir'.)or, and levea any be extendeil as the growth of the city or of several 
cities and multiplj^ing villas and plantations may require, until the improvements embrace and 
encircle the entire lake and all its connections with other waters. This with the aqueducts and 
canals will encompass New Orleans with a sanatory cordon of puie running water, which will shield 
4 H E 



26 CONTEIBUTIONS, ETC. 

it against the ingress of all malarisi generated outside of its limits. Malaria, like the mythical witch 
of Scotland which chased Tarn O'Shanter from Kirk AUoway to the Dooii, cannot cross running 
water. Residences u[)on islands surrounded by river or ocean currents, if their sites are kept clean 
from local filth, are usually very healtliy. The use of drainage is to prevent the origin of local or 
indigenous malaria. The yellow-fever ])oison is probably a tropical plant, of the fnn(/us family, to 
which the mushroom, lichen, ah/a, and all the mouMs belong. This exogenous and imported poison 
will spread wherever there is heat and moisture to nourish it, and it can ordy be excluded by 
rigid quarantine. It originates in tropical filth, but, like the small-pox or itch, whether it is a 
minute aterous or wingless insect, ov the sj)ore of a microscopic fungus or other cryptogamous plant, 
Tiourished first in some filthy hovel of the torrid zone, it will poison the cleanly inhabitants of all 
cities of the temperate zones at a less elevation than 1,000 feet above the sea. 

The first beautiful effect of tlie apjilication of this plan will be seen when the breakwater is 
constructed a half mile in front of the termini of the Lake end and Pontchartrain Railroads. The 
cyclones will dash the storm-waves against them, and roll them through the gateways of the ships 
and scour out the passages ; but they will disperse their force harinlessly in the wide and quiet 
liarbor, and never strike the shore ; wliile tliey will transform the breakwater into a long line of 
islands made by the saiul and shells thrown up by the tempests, and which will bury the piles and 
fascines out of sight. But the materials of which they are formed, and especially the willow, 
cypress, and other trees of the swamps, will grow and form a lovely display of living green. In tiie 
course of a few years these islands will make smooth and broad sandbeaclies towards the ce:iter of 
the lake, and form crescents of semi-tropical lands parallel with the eutire encircling harbor and 
shore, more beautiful than the lovely ring-shaped atolls of the Pacific Ocean. Tliey will be crowned 
with bath-houses, hotels, and residences of merchant princes and planters, displaying all the varie- 
ties of convenient, chaste, and gorgeous architecture, and ornamented with all the fruits and flowers 
which will grow in our almost winterless clime. The glories of Clialco, Tezcuco, Como, and Mag 
giore will be eclipsed by the variegated i)ictures of elysian loveliness and magnificence which the 
future will display upon the bosom and around the shores of Lake Pontchartrain if this plan for its 
im[)rovement shall be adopted and faithfully applied. The commerce of a city greater than ancient 
Rome will float upon its surface, and the millions of its inhabitants will find healthy and profitable 
employment, while they will be refreshed and invigorated by its purifying waves and balmy gales. 



:pj^e.t III. 



AN EXPLANATION OF THE PRINCIPLES UPON WHICH THE PLAN FOR THE CONTROL 
AND UTILIZATION OF WATER-CURRENTS IS BASED, 



AND ITS APPLICATION TO 



THE MISSISSIPPI RIVER, 



CONNECTED WITH A 



GENERAL LEVEE SYSTEM. 

A GENEEAL PLAN FOR THE IMPROVEMENT OF ALL RIVERS -AND HARBORS BY THE PROPER 

GUIDANCE OF MARINE AND FLUVIATILE CURRENTS TO ERODE CHANNELS, 

TO FORM NEW LAND, AND PREVENT INUNDATIONS. 



INTRODUCTORY. 



Unfortunately all attempts made and levee systems applied to control the Mississippi have been 
superficial. They have no reference to the bottom current. If that is neglected levees cannot be 
protected, and crevasses by undermine cannot be j)revented. The channel of the Mississippi can 
only be deepened, bars can only be removed, levees can only be guarded, and overflows can only 
be averted by controlling and guiding properly this bottom current ; and that cannot possibly be 
done by any other mode than by jetties constructed upon the plan recommended in the following- 
essay. 

The levee system properly apj)lied to the whole river from New Orleans to Saint Louis, pro- 
vided that the jetties recommended are applied to the lowest bar first, and then successively to 
each of the others above, and also above the concavity of each bend of the river, and connected 
with the top of the levee and the bottom of the river, will cost less than $10,000,000. 



THE OUTLINES OF A PLAN 



FOR 



ConirolUng the Mississippi River so as, first, to guide its current and protect levels; second, to save its 
banhs from undermines ; third, to make batture, or alluvial deposits where they are needed; fourth, 
to remove its bars without dredging ; and fifth, so to deepen its channel by erosion as ultimately to 
prevent overfloios. 

The main objects of the plau are to give permaueuce to its banks, and to pi'event the shifting 
of its bed ; to preserve its islands and its shores with all the property upon them, and at the same 
time to make it navigable, at the lowest stage of its water, to ocean vessels of the largest size. 

This plan was elaborated many year.s since, pre^iintel to the N"e>v Oii'^ans Acidemy of Sciences 
in 1866, ai^proved and adopted by it January 8, 1888, and sent to the various Academies of Sciences 
of America and Euroi)e during that year. 

This plan has been very generally approved, but the most useful principles of hydraulic engi- 
neering embraced in it, especially the i)roper angulation of the jetties with reference to the artificial 
current-channel intended to be formed by^their guidance of the natural current, has never so far been 
applied either in America, Europe, or elsewhere. 

The plan is based on these two principles — 

1. The angle of reflection of water in motion is equal to the angle of incidence minns the resist- 
ance. (See Plate 1, Diagram 1.) 

2. The walls of all jetties for controlling water, where their foundations are mud, sand, and 
other friable materials, or where they do not rest upon rock, or undisintegrable materials, must be made 
of brush, latticed-diagonalized-cribwork, or other non-reflecting substances ; or so faced with such 
materials as to break and dissipate the force of the currents they ai'e intended to control by hurling 
the particles of water which compose them against each other, and preventing their downward 
reflection, and consequent undermining action. None of the surfaces of the materials should be 
smooth, but crossed, or corrugated. A simpler and more comprehensive description of these con- 
trolling or guiding jetties may be given as follows: They are properly angulated reflecting walls faced 
with non-reflecting materials. Wherever it is applied it should control the bottom currents. 

I. — THE MATERIALS FOR THEIR CONSTRUCTION, AND THEIR FORMS. 

(See Plate III, Diagram 1.) 

These may be varied to suit the localities intended to be improved and the depth of the water 
in which they are to be used ; but none should present plain surfaces. 

1. To control currents too deep for their beds to be reached by piles, and where it is desirable 
to guide the bottom currents, especially those of the Mississippi, at depths of from 40 to 180 feet, 
or at a greater distance below the surface, they should be made of strong cubical-formed diagon- 
ally-latticed caissons filled with loose stones, of convenient size for handling, and for being anchored, 
and linked together in a row or in rows upon the beds of the deep bottom currents; or they should 
be made of felted fascines strongly bound and heavily ballasted to resist the first shock of water- 
logged stumps, trees, and bowlders of clay, or other heavy substances hurled against them by the 
bottom current, and which may remove them from their alignment and connection with the portions 
of the jetties in the shallow water, constructed of piles and fascines, and of which these heavy 
cribbed caissons are intended to be the termini in deep water. (See Plate III, Diagrams 10, 11, 
and 12.) The diving-bell should be used, to see that they are compactly adjusted on the deep 
bottom to form an obstruction to catch and compact the silt and deflect the current. 



32 CONTRIBUTIONS TO THE 

2, For all shallow water iu our soft-bottomed rivers, and the inud and sand bedded lakes, 
bays, and estuaries, the jetties ought to be made of piles and brush fascines — materials which grow 
in every swamj) and bottom-land forest. The cypress, tupelo gum, swamp ash, and other watery 
growths, and the tall young willow and cotton wood saplings, which form the winter " towheads" 
of the recently-formed areas of batture, and line the margins of all the bayou and river banks, invite 
their use. No rock is needed for the construction of these shallow-water jetties. They should be 
made as follows : 

Two rows of piles 12 feet apart, the piles in each row 8 feet distant from each other. Each pile 
to be made of a stout tree with the baric to be left upon it, and the rougher and more corrugated the 
better it will answer the purpose as a non-reflector in resisting the undermining action of water. 
The pile shoidd be properly notched at the lap or upper end to receive the attachment of one or two 
girders or coiniecting poles, and sharpened at the hitt or root end into a triangular ov quadrangular 
point to be driven easily and to a sufficient depth with the butt douuncard (see Plate III, Diagrams 
from 1 to 7), in order that it may stand firmly when the currents make deposits around its base. 
It will then be placed on the principle of the obelisk and in the natural position of the tree. The 
fascines should be made of bushes as straight as possible, 15 feet long, and each one should be 
fastened with two icraps around four stoi;t sticks radiated at right angles to the saplings or switches 
of the fascine of which these two circles of radiated sticks form the frame. Bach stick should be 
barbed at one end and shar])ened at both ends. It should be cut below a stout limb at least an 
inch thick, and this limb should be shaped by the hatchet into a barb. The points of these sticks 
should i^roject at least a foot beyond the sides of the fascine. The wraps should be far enough 
ajiart to x^revent any hindrance to convenient carriage upon the shoulder, and their dimensions 
should not be too great for the strength of an ordinary man to handle them. They must be 15 feet 
long in order to x)rqiect at least 18 inches beyond the lateral lines of the rows of piles, between 
which they should be i^acked in alternate floors or layers at right angles to each other, and then 
rammed and felted together with a heavy and properly constructed hrush-paclcer. CSee Plate IV, 
Diagrams from 7 to 11.) The object of the barbed wraps is to make them hold to the bottom when 
driven down upon it, and to fasten lilie felt to each other when packed together, and to obviate the 
use of stone to weight them down. 

After the space between the piles is thoroughly filled, the whole work should be girded together 
by 15 and 24 feet willow x)oles spiked into the notches mortised near the top of the piles; the 15- 
foot poles crossing the line of the breakwater or jetty at right angles, and the jioles 24 feet long- 
crossing these 15-foot ])oles and each other diagonally on the central line of the top. 

These breakwaters will resist the storms of the G-ulf, and form the nuclei of islands and sand- 
spits. They are buried in mud and sand, and will grow where they are planted and display living 
lines of willows and cypress, and the usual growth of our marsh-lands. I recommend these struc- 
tures as the strongest, cheapest, and most permanent breakwaters and jetties for all our southern 
sea and river hydraulic defences. Nothing will be found suijerior to them for stopping- crevasses. 
I suppose that the work will be faithfully executed, and its character may be greatly varied. I 
only recommend it for water less than 40 feet deep. They are not only cheajjer than iron, but 
more durable. 

II. — THE LOCATION AND PROPER ANGULATION OF JETTIES. 

I. No jetties intended to control water-currents, to deepen, and at the same time to make per- 
manent chaunels, of regular forms, and without the aid of dredging, ought ever to be made par- 
allel, for these reasons (see Plate I, Diagrum 5) : 

1. Although parallel jetties may be nuide to guide and to confine a current, they will not 
accumulate or double its erosi^'e force by reflection from each wall, or from both jetties upon a g-i^-en 
line, so as to form a channel of a regular and uniform shape and depth. The globuhir particles of 
water between parallels move along juirallel lines until thej^ strike some obstruction to their motion 
which will deflect them upward, downward, or laterally at angles given by its shape. A sunken 
shi]) in the channel or a rounded stone or mud-lump will part the current aiul hurl it with dangerous 
undermining force against both jetties. At the mouths of river's, and especially at the passes of the 



SCIENCE OF HYDEAULIC ENGINEEEING. 33 

Mississippi, into which vessels entering meet those Avhich are departing, they often collide and sink. 
The prow of the sunken vessel points up stream while the stern is turned seaward by the current- 
The currents jjarted by its prow are deflected with erosive force against the jetties and cut deep 
troughs. The eddies whirl behind the stern and meet and mingle, forming obstructing lumps, bars, 
or islands. Clusters of trees tied together Avith vines, drifting seaward, and anchored by their limbs or 
roots, or huge bubbles of clay lifted by vast volumes of gas generated by hammocks of logs, brush, 
leaves, and other vegetable matter buried deeply in the strata of the ancient Delta, produce similar 
effects. A large water-logged tree-trunk three or four feet in diameter, or a ship sunk near one 
jetty and lodged angularly to the current, will deflect its whole force against the other, which in 
turn will be reflected diagonally in a contrary direction, and give it a zigzag course from loall to icall 
for a distance of many hundred yards, or miles, proportioned to its velocity and the angle of the 
deflecting obstruction. Then the obstruction can only be removed by blasting dredging, or other 
mechanical force ; and the channel can only be straightened and deepened by the scraping or 
spading of the pump, dredge, or other expensive artiflcial contrivance. The cross-sections of sound- 
ings below such obstructions across the ])arallel-jettied channel exhibit irregular curves of various 
kinds, and reveal a trough, shaped very awkwardly, difflcult and dangerous for navigation. These 
facts are so obvious as to make unnecessary even these simple diagrams for their illustration. 
(Plate I, Diagram 5.) 

Properly converged jetties reflect the water at angles corresponding with their angulation. 
They converge the water and accumulate it into an erosive current continually acting with a cork- 
screw, drilling, and boring motiou, cutting, with the combined power of the auger and sand-blast, 
upon a fixed line as permanent as their position. This current, always moving upon a friable bot- 
tom of mud, sand, tenacious clay, or even disintegrable chalk or sandstone, will biuy in it or remove 
from it any object whatever. It wUl cut away mud-lumps and islands, float off any wooden or other 
buoyant obstacle, and by excavating the fragile bottom, guided downward by the reflecting sides 
of an iron shii) or block of stone, it will bury the solid and heavy obstruction and shape the bottom 
of the channel in a form corresponding with every other part of the trough excavated by the guid- 
ance of the angulated and converged jetties. (See Plate I, Diagram 4.) 

2. Parallel jetties cast no accumulated erosive current beyond their points. The water wldch 
runs through them is immediately diffused and spreads out in all directions. They are as unscien- 
tific as cylindrical tubes attached to the ends of the hose of fire-engines for throwing water. They 
scatter tuell, but will not squirt- far. Pipes like inverted cones, sections of which are the lines of con- 
verging jetties, propel the water much farther with concentrated erosive force, and will form an 
eroding current which will remove obstacles far distant beyond their extreme points. (See Plate V, 
Fig. 1.) Within the banks of rivers battore will always form between their points and the banks, 
and against the banks along their curving bends at distances below their ^joints proportioned to 
their angidation and the velocity of the current. At sea, upon shallows where it is necessary to 
connect their angles throughout their extension to guard them against the ordinary currents and 
the more violent action of those produced by storm-winds, which would break through them if they 
were disconnected, cut trenches across the artificial channel, and fill it with sand on either side of 
the gaps ; if they are properly constructed the batture will fill up only the angles and leave a trough 
open with its sides parallel and aligned with their jjoints, while vast areas of land will be formed 
on each side of them from their points to the mainland. 

II. Jetties should never he located at right angles to the current, or to the line of the banlc of the river 
they are intended to protect, for these reasons : 

1. Although such jetties confine a river or sea current and give it a greater depth, they do 
not guide it either above or below their points. The central current flows directly on at right angles 
to their lines. The left and right flanks of it strike the jetties perpendicularly. Their under cur- 
rents checked are thrown up and down, and excavate their foundations if they are smooth; or if 
they are latticed, corrugated, or made by other means non-reflecting, they accumulate deposits 
against them, and spread ovit laterally. One portion acts directly against the whole volume of the 
central current which whirls it against the bank below the jetty and excavates at the same time 
the bottom below the foundation of the jetty-point, and the other portion above is thrown directly 
against the bank and undermines it, and destroys the connection of the jetty with it. Unless addi- 
5 H E 



34 CONTEIBUTIONS TO THE 

tional works arc con^strncted giving tlie fasteniug of the rectangular jetty to the bank the form of 
the letter T, ^ portion of the river will cut oft" its connection with the bank, pass through the gap, 
and form an island of which the jetty will be the nucleus or frame-work, and one of its diameters. 
This reveals two other objections to this angulation of jetties already stated. 

2. The rectangular jetty, requiring one or more extensions L or T at its base or connection with 
the shore is too expensive; and if these additional works are not constructed to secure the land 
from toidermine and submergence it will make crevasses and swamps; and it is, 

3. Dangerous as well as ivorthless. 

I have heard tliese arguments urged in favor of this plan of rectangular jetties : 

1. The rectangular jetty is. less expensive than the diagonal, or the deflector, or converger, 
which are different names for the same thing, because it is one of the sliort lines of a right-angle 
triangle, while the diagonal is its longest line, or the hypothenuse. 

To this I answer tliat the entire hypothenuse of the rectangular triangle need never be used on 
the Mississippi Ei^er or elsewhere to protect the banks, to make batture, to remove bars, or to 
deepen channels by removing other obstructions. Only a part of this line properly angulated is 
necessary for the construction of the jetty. Its length will be proportioned to the width of the 
river and the depth of the water, and the distance of the bottom current from the bank. Where 
the river is the widest the jetties should be the longest; but in such places the current is the 
sveakest and the water the shallowest, and consequently the jetties may be made in the least 
expensive manner, and they will cost less than short jetties in deep water flowing with swift and 
strong currents, and which will require heavj" and expensive mattresses or caissons for their con- 
struction, while these long jetties, to confine and guide the water to make it erode deep channels 
across bars and shoals, can be built of cheap piles and felted fascines without the additional 
expense of stone or iron, so as to be as strong and durable as the most permanent works of man. 
(See Plate TV, Diagram 3.) 

2. It has been said in favor of rectangular and parallel jetties that Sir Charles Hartley 
removed with them the bar at the mouth of the Danube. This is a mistake, as will appear from 
the following diagram of his work. After a survey of the Danubian mouths in 1829 various efforts 
were made for deepening the bar of the Sulina mouth, which was deemed the most practicable, and 
which had a natural depth of 10 feet. The useful idea occurred to tlie engineers as early as 1857, 
that if the water could be confined to the ordinary width of the river al)ove its delta, its current 
would erode a channel across the bar at least equal in depth to that which it maintains between its 
natural banks for a great distance above its outlets into the Black Sea. It was also correctly 
inferred that there would be no extension of the bar beyond the jetties, because a sea current from 
the north passes from the east by the Crimean coast against the western shore, touching the mouths 
of the Danube, and flowing into the Mediterranean through the Bosphorus, the Sea of Marmora, 
and the Hellespont. In 1861, after numerous efi'orts had been made to effect this confinement of 
the water by rectangular jetties, it was determined to connect the works and to run two parallel 
piers nearly 600 feet apart entirely across the bar, and to force the whole volume of water of the 
Sulina i^ass to flow into the sea-current between them. The jetty- work with its extension was com- 
pleted in 1871, and a depth of 20 feet was secured. But an examination of the operations which 
were at last successful will prove that the engineers did not understand the principle of converg- 
ing jetties and their proper angulation. Their object was simi)ly to confine the water between par- 
allel walls, supposing that flowing through such contrivances it would dredge a regular channel of 
the required depth. The idea of a current deflected from a jetty converged from each side at a 
proper angle to the line of erosion, so as to accumulate an eroding current upon it, which, by its 
onward gyratory or auger-like motion, would cut out a deep mid-bank channel equidistant from the 
guiding jetties, seems not to have occurred to their minds; and many engineers of considerable 
reputation suppose that the removal of the bar was effected by the instrumentality of the parallel 
piers. 

A simple inspection of the work demonstrates that the erosion was effected by a part only of 
the plan, where the principle of convergence was brought into action. (See Plate II.) The bar 
was removed by an accumulated converged current, produced by a small ]iortion of each jetty 
where both were directed angularly or diagonally upon a part of the line of erosion. Fortunately 



SCIENCE OF HYDEAULIC ENGINBEEING. 35 

t 

in connectiug the iipper ends of the jetties at X and W with the beginning of the parallels at Y 
and Z, their lines were converged, and although they were improperly curved and unequally angu- 
lated, instead of having been run straight and at equal angles uiDon the central channel line cc, yet 
they converged and doubled the force of the lateral currents on the line of the present navigable 
cliannel, which they formed exclusively, to the deep water of the sea. The only aid given them by 
the parallels was the protection they aftbrded as breakwaters against the storms and currents of 
the Black Sea. 

The work of dredging or scouring out the channel was the exclusive work of the portions of 
the south jetty from a to h, and of the north jetty from c to d, which accumulated a gyratory erod- 
ing current all along the bottom of the present channel A A, which deviates widely from the line 
c c, intended for its bed. 

I dislike to say that this happy effect was the result of the accidentally converged connection of 
the rectangular and parallel jetties. They certainly inteuded to connect them in order to confine 
the Avater and make it flow between the parallels planned to remove the bar, but I think the accu- 
mulated current which the convergence of the jetties produced, and which did the principal part, 
if not the lohole of the worlc of erosion, was unintentional on the part of the engineers. I do not 
think they intended the convergence to produce erosion, because I have heard that they still 
recommend parallels for the purpose. The irregular winding channel AA which they made proves 
their ignorance of the whole theory of the proper angulation of jetties, and at the same time it 
demonstrates conclusively its correctness. If you will examine closelj" the diagram you will see 
that the navigable channel AA deviates from its proper midway course at H, and runs diagonally 
across it to the north parallel at I, which there deflects it eastwardly to J. The divergence given 
to the channel from its midway course at H, and its dangerous direction to I, is evidently caused 
by the erroneous angulation of the jetties X d and W h. The jetty W h converges towards the 
central channel line C at a greater angle than that made by the opposite north jetty X <? ; 
and, con sequent! 3^, the line of erosion, or the channel cut by the accumulated currents they pro- 
duced, is deflected from H to I nearest to the jetty converged with the least angle toward the 
central line C C. This will be found by experience to be a rule without exception: Jetties con- 
verged at equal angles ^ipon a central line will cause the water-current which they guide to erode a channel, 
the deepest part of ichich channel will he %ipon that central line equidistant from both jetties. If one jetty 
is run toivards it at a less angle than the other, the channel ivill he cut nearest to the jetty with the least 
angle. (See Plate I, Diagram 2.) Consequently, a better jilan for the construction of the Danubian 
jetties would have been to have constructed two straight jetties, in 1829, from the extreme northern 
and southern points of laud at that time at e e, and to the points// on the outer crest of the bar, 
and converged at equal angles upon the central line P P. Batture froju the river floods would have 
fllled all the spaces between the points of the jetties and their upper connections with the shores, 
and the lines, 600 feet apart, parallel with the central line of the channel P P ; and the sands of " the 
stormy Euxine" would have extended its shores to the ends of the jetties and against their exterior 
sides. 

It is best to diverge two sea-walls at angles equal to the angulation of the jetties from their extreme 
points. Nature, by its hydraulic system for removing bars and opening harbors at the mouths of 
great navigable rivers, indicates this plan as the best, and even gives us plainly the proper angu- 
lation for jetties, if we choose to imitate or assist her operations. I have heard it said that nature 
works with parallel banks to deepen the channels of water-currents. This is inferred from the fact 
that the banks of rivers, whether straight or curved, are usually parallel ; hence the conclusion is 
deduced that in our eiforts to remove bars and to deepen channels our guiding jetties or artificial 
banks ought to be made i^arallel. This would be true if the premise was correct ; for a natural law 
is always our safest guide when we wish to effect by art what nature performs in obedience to the 
direction of the Great Creator by the physical forces He has given to her. 

But the premise is false; for nature does not guide or deepen the currents of either rivers or seas • 
with parallel hanlifi- On the contrary, I safely and positively assert that nature ivories with diagonal 
jetties exclusively to deepen all channels, and makes their banks or lateral margins parallel by diagonals 
converged to the lines of the direction of the currents, whether they are fresh water or salt, flu- 
viatile or marine. These natural jetties are formed of a variety of materials, rock, clay, wood, or 



36 CONTRIBUTIONS TO THE 

compounded detritus of various kinds, either undisintegrable by water or less friable and more 
tenacious and fli-mly fixed than the banks and bottom bars which oppose the currents which they 
direct against them. In rivers a diagonally-projecting rock is a natural jetty which will hurl the 
current against the opposite bank. If the baiik which receives the erosive force is composed of 
strata of soft stone or of earth it will undermine it and wash it away. The Mississippi River, after 
it receives the Ohio, and leaves its cliffs of rock and enters its vast alluvial area which has all been 
stratified and rearranged in layers of sand, clay, or mixtures of both, by the floods, and the sleepless 
and tireless action of its "perpetual motion" for ages, is performing this operation before our eyes 
to-day of first destroying and then paralleling its banks by diagonal jetties. 

Let us examine a single point on the right bank, from which descends a titanic current which 
strikes a curve in the left bank a mile below and undermines it and swallows it up with everything 
which grows or which is built upon it. Let us take this destructive, deflective, projecting point, 
and dissect, anatomize, and make a geological section of it. Its flat top is crowned with a forest of 
ancient trees and a jungle of cane and bushes, and a variety of vines tying and tangling all its vege- 
table growth together. Its slope to the water's edge is terraced usually with from three to five steps 
made by the annual inundations of as many years, marked by successive yearly deposits, the oldest 
covered with full-grown cottonwood and willow trees, and the newest with saplings and switches 
of the same growth; and upon the sand strown by the last rise and left bare by the receding flood, 
we find the downy seeds of these trees clinging to the newly-formed hatture and springing into life. 
In time for the next vernal rise of the river they will have grown several feet in height, and covered 
the sand-bar as thickly as grass in the meadow or wheat in the field, ready to strain the mud from 
the water of the flood, and to elevate the terrace on which it grows to the height of the one above 
it. Beneath the water-level we find the sloping bottom of the point projecting diagonally, and all 
covered with pure sand down to the deepest depression of the river-bed. 

Now let us cut through this anguJated, guiding, and destructive jetty, and ascertain what is its 
core, nucleus, or foundation. We will find it at a depth of from 80 to 150 feet resting upon clay. 
It may be the wreck of a coal-boat, or some other vessel. Usually it will be a cluster of trees and 
bushes tied together with grapevines, bamboos, or creepers. The river undermines a portion of 
the primeval forest, and whole clusters of them bound together by vines fall into the water, and by 
the heavy masses of clay grasped by their roots they are sunk to the bottom where they are occa- 
sionally securely fastened, and by catching the water-logged brush, bowlders of rolling clay, and 
detritus of all kinds lodged against them and compacted into tliem- by the bottom current, they 
form the foundation of a deflecting jetty which can never be moved. Even if the river cuts its 
way around one of these sunken tree-rafts, it usually leaves the mass as the supporting foundation 
of an island. Most of the islands of the Mississippi have l>een formed by these clusters of trees. 
Occasionally they float for a while after falling into the strong, deep current which erodes the bank ; 
but where the river widens and shallows its volume over the areas of tenacious clay they "ground" 
and adhere to the bottom and form the nuclei of islands, which act the part of V-shaped jetties with 
their points up stream, which part and deflect the current and cave in and curve the opposite shores. 
Unless jetties are situated in such a position as to prevent the undermining action of these deflected 
currents, the islands will grow continually at the expense of the banks on either side. 

These illustrations will be suiflcient to show that the river-currents perform their work with 
diagonal and not with i^arallel jetties. The parallel shores are formed by the eddies which whirl on 
either side of the eroded trough made by the converged and accumulated currents, and which deposit its 
excavated materials in lines parallel with its course. Sea currents also are operated by diagonals and 
not by parallels. N'ature ivories with converged diagonal jetties in removing bars at the mouths of rivers, 
and also those between islands, or betioeen islands and the mainland. Ever since the N'oachian deluge, or 
what geologists term the Glacial epoch, Nature has been striving to mingle the deep channels of the 
great rivers with the deep currents of the seas. This ahna mater is not pressed for time in per-- 
forming the work which God has given her to do. For nearly four thousand years she has con- 
tinued this work with vxnerring wisdom and omnipotent power, and she has taught us how to aid 
or imitate her mode of removing bars by showing us that all these rivers enter the sea with trumpet- 
shaped mouths. The diagrams of the Saint Lawrence and each mouth of the Mississipi^i, and all 
other great rivers, prove this. They pour their waters into the great deep through divergent 



SCIEFOE OF HTDEAULIO BNGINEEEING. 37 

shores, or banks which are natural jetties diverged seaioard, and converged upward towards the 
inner crest of the bars. 

I call the attention of geologists and physical geographers to this important fact, which also 
deserves the careful consideration of all hydraulic engineers entrusted with the task of removing 
bars at the mouths of rivers. They not only enter the sea trumpet-mouthed, or with divergent 
banks, but the central line of their currents between the extreme points of land which terminate 
them is directed at right angles to the sea currents which they enter. Thus the mouths of the 
Danube open at right angles to the Black-Sea current, which flows from Odessa south across the 
Sulina mouth to the Bosphorus. The Saint Lawrence opens its vast jaws and discharges its huge 
volume at right angles into the great Arctic current which descends across it, and also across all 
the bays and river-mouths from Davis's Straits to Floridn, The mighty Amazon, between diver- 
gent banks whose extreme sea-caj^es are 180 miles apart, pours its mammoth tide into the Atlantic 
current which flows from Cape Saint Roque at right angles to this giant river-mouth, and at the 
same angulation crosses the mouths of all the rivers on the coasts of the Caribbean Sea and Gulf 
of Mexico, as it flows on northwardly^ along the eastern shores of South, Central, and iN'orth 
America, between Cape Saint Roque in Brazil and Cape Sable in Florida, where it forms the Gulf 
Stream. 

All the river-mouths of the whole earth demonstrate the same fact. I will now show the reason 
for this wise providential arrangement of these river-mouths and the sea-currents with which they 
mingle, and the oj)eration of this wonderful hydraulic plan of nature to secure the beneficent object 
of removing the obstructions to the international commerce of the world. The proper study of it 
Avill convince any enlightened engineer that any obstruction at the entrances of bays and the 
mouths of rivers, made by shoals and bars, may be removed by assisting nature in the use of these 
marine and fluviatile currents, by the proper api)lication of the hydraulic principles which she uses 
in connecting the deep channels of the rivers with the navigable currents of the oceans and seas. 
For the removal of all obstructions in bays like the Delaware, Chesapeake, Mobile, and others, the 
jetties ought to be angulated so as to utilize the scouring action of both the floic said ebb of the 
tides, and the influx and outflow of the storm-waters. This can be easily effected by constructing 
them upon the plan of the diagram for making a ship-channel between Heron Island and the main, 
land on the west of Mobile Bay. It resembles the worms of Virginia fences making a lane, with 
the angles of their panels opposite and equal. (See Plate III, Diagram 9.) 

Another reason why nature has usually made the mouths of the great rivers and many bays 
open trumpet-mouthed, and at right angles to the deep-sea currents, is that their currents may be 
so checked that they may form safe harbors or easy entrances to vessels. If the current of any 
great river, like the Amazon or Mississippi, instead of entering one of these ocean streams at right 
angles, were iningled with it at an angle of from 11^° to 45°, the eJcmuzesis, or the suction of the 
ocean current applied to that of the river, would produce consequences some of which would be 
disastrous beyond our conception. Eroding velocity and contraction of its channel would certainly 
ensue, and there could be no safe and easy navigable entrance formed, such as now exists, for the 
admission of vessels. (See Plate V, Fig. 3.) 

In order to show that nature uses this trumi^et-mouthed form opened at right angles to these 
ocean currents to remove the bars of rivers I will take only one example to illustrate this fact. The 
Southwest Pass of the Mississippi will be sufficient for our purpose ; and I select it in i)reference to 
the months of the Saint Lawrence and Amazon, because the bars once obstructing their outlets 
have long since been removed by their converging jetties, while the process of the removal of that 
of the Southwest Pass by the same instrumentality is yet in operation. (See Plate I, Diagrams 3 
and 6.) 

The mouth of this pass opens directly to the southwest and receives within its divergent jaws 
or natural banks the full force of the southwestern gales and thunder-gusts, and the great cyclones 
whose centers move to the northeast. The tides which enter it, and the- currents which are driven 
furiously into it by the tempests, strike its banks which are converged upon the central line of the 
inner crest of the bar. Deflected upon it as they rush in from both divergent banks, they are con- 
verged and accumulated upon it, and loosen all its friable structure, which is carried out by the 
ebbing tides and the oiit-rush of the swollen waters heaped upon the inner crest by the storms ; and 



38 CONTRIBUTIONS TO THE 

while a portion is borne into the ocean cnrrent and transported far away, the rest of the wreck of the 
bar is stranded on either side of the trumpet-shaped outlet, to extend the extreme points of land. 

Above the bar the current of the pass pours into the deep trough cut by the concentrated 
influx of storm-water, and by its lateral eddies parallels the banks up to the new inner crest of the 
bar, which is advanced continually by the successive tempests and tides towards the deep troi)ical 
current of the Gulf which comes from the coast of Texas and Southern Louisiana after curving 
around Northern Brazil, Guiana, Venezuela, Central America, and Mexico, but whose eddies at the 
mouths of the passes whirl westwardly opiiosite to its eastward course. All currents^ ivhetker 0/ 
rivers or oceans^ mal<e eddies along the hanlis and. shores which they erode., and which whirl as counter- 
currents opposite to the direction of rivers., and of the great equatorial and polar ocean streams. 

Ignorant of this law of all currents, whether of rivers eroding their banks or of oceans wearing 
away their shores, some of our hydrographic engineers have made it apj)ear that the great tropical 
current at the mouth of the Mississippi flows Avestwardly towards Texas. They mistake the surface 
currents caused by easterly winds, and the eddying counter-current hurled upward by the warm 
Gulf Stream, which at a depth of several thousand feet is eroding the ancient rocks of the foundations 
of the continent as it flows on towards the coasts of Alabama and Florida. Yessels and boats 
ascending the Mississippi run next to the curving and caving bends of the river, because there they 
find counter-currents which bear them up stream ; but they know that the river does not flow north 
but to the south in spite of these eddies. 

To enable the Mississippi River and the tropical currents to finish in a year the work of remov- 
ing the barriers between them, and which Nature unaided will effect sloAvly but surely in a few 
centuries, let us assist her a little, guided by the diagram with which she has illustrated her own 
hydraulic law, or rule of action. ' 

Let us take the diagonal lines of the section of a trumpet, or truncated cone, which designate 
the natural banks or jetties of the South Avest Pass converged to remove the inner crest of the bar, 
and reverse their angulation and \)Ouit them to the outer crest of it, and construct uj)on them our 
artificial jetties. Let them be made of piles and fascines as recommended in this essay. The water 
is all shallow from the extreme points of land to the outer crest of the bar. No stone will be neces- 
sary to weigh them down. The wood which forms their frame-work will outlast iron under water 
either salt or fresh. The Teredo navalis and other wood-eaters cannot reach them ; for a single 
annual inundation, a cyclone, or the ordinary gales from the north and southeast, in a year after their 
completion, will bury them with batture from the river and sand from the Gulf. Two ribs of land 
12 feet high above the level of the sea, densely covered with two lines of thrifty and beautiful trees 
and shrubs, will mark their graves, which will outlast the monuments of Egypt, and remain 
unmoved until "the trump of Doom" shall rend all tombs. The seaward points of the jetties may 
be advantageously diverged at the same angle with their convergence for a variety of useful purposes. 
They will in some instances gather the force of currents from the sea during storms, and aid by. 
their influx and outflow the erosion of the bar, and the formation of land in the inner angles of the 
jetties on either side of the navigable channel, and strengthen the whole work ; and their divergent 
sea-points may be suitably formed into light-houses, signal-stations, and forts to guard the pass. 
It Avould consume too much time to demonstrate the important fact, which I will simj)ly state, that 
by jetties thus angulated it costs no more to obtain a depth of 60 feet across the bar of the Southwest 
Pass, or any other over which the same quautity of water flows, than it does to secure a channel 30 
feet deei). If by the convergence of the jetty-points on the outer crest of the bar to a distance of 
880 yards of each other the channel is scoured 30 feet deep, jetties of precisely the same dimensions 
and cost brought to half the distance, or 440 yards apart, will inevitably dredge one ticice the depth, or 60 
feet. They will force the current to do this without the aid of a dredge-boat; and they will main- 
tain that depth of water without any assistance /orewer as long as it flows between them. 

Converged jetties act as a continual guard to the channel. They deepen the trough and parallel 
the sides with its excavated materials. They are buried out of sight in the silt, and they remain 
concealed as long as the current flows in the trough which they have made. But if a sunken wreck 
or any obstacle in the channel shifts it to either side, the diagonals are uncovered by its erosion, and 
they act upon the current as they did at first, and again deflect it to its proper course. 

I have not the space to show how the bars of the Amazon, Orinoco, and many other great rivers 



SOTENCE OF HYDEAULIO ENGTNEEEING. 39 

have been remo"s^ed and their deltas swept away by the combined action of the flu^^atile and marine 
currents guided by natural diagonal jetties. The deposits of some of them, lilce those embraced 
between the great divergent jaws of the mouth of the Saint Lawrence opened widely to receive and 
accumulate the high tides of the Arctic current flowing along the eastern shore of British America, 
have all been scoured out to a bottom of solid rock, Availed with the same material, swept bare of 
all earthy and soluble matters. Deep channels or straits, between continents and islands, are kept 
open by the deflected currents guided by their angulated shores. (See Plate III, Diagram 9.) 

From all these facts the following conclusions are deduced, which I will only have time and 
space to give in the form of brief practical directions for the guidance of engineers. The same rules, 
varied by the genius and common sense of those who have to execute the work of controlling and 
utilizing water-currents, may be applied to any river, and especially to those parts of them which 
are unobstructed by rocky ledges, and whose beds are composed of sand, clay, and minutely-dis- 
integrated matter, like the Mississippi from Cairo to the Gulf. They may also be applied to those 
which are obstructed by falls, and flow over beds of stone and between clift's of rock ; but in such 
cases the erosion caused by the properly-angulated jetties must be aided by blasting and cribwork 
of wood and stone. I will direct your attention exclusively to the Mississippi Eiver from the mouth 
of the Ohio to the passes, and give these directions to accomplish the following important objects ; 

1. To open a navigable channel which at the lowest stage of water will have a depth of 30 
feet, and which may be extended up the main tributaries to the Appalachian Chain and the Eocky 
Mountains. 

2. To give permanence to the present banks of the river, and also to i)reserve those of its 
islands; or, in other words, to secure the boxmdary lines of the lands on its banks and islands from 
being cut and destroyed by tlie shifting of the current, and to confine the current to an unchanging 
bed, which will be only altered by being deepened. It will not be permitted to shift laterally, and 
it will be formed between the present banks, including those of the islands, so that no man's land 
will be lessened or injured by it. On the contrary, by contracting the width of the river the areas 
of the land fronting upon it in many instances will be greatly enlarged. 

3. To utilize a general levee system which will be permanent, and which will make inundations 
by overflows, or crevasses by undermines imi)ossible. 

Direction 1. 

Construct levees of earthwork on the most suitable ground for the purpose and the jetties to 
protect them simultaneously. The levees should be elevated above the high-water marks of the 
portions of the river to which they are applied, and jetties at the same time should be built above every 
caving bend, and not in it, extending from the top of the levee to the bottom current of the river. 
Eows of piles 12 feet apart and standing 8 feet apart in each row, with spike-wrapped fascines felted 
between, the piles placed and the brush packed, and the whole work girdled as I have already 
described, should be used where the depth of water does not exceed 40 feet. Their extension to a 
greater depth will have to be made with mattresses or caissons weighted with stone. The angu- 
lation of the jetties must be given to suit circumstances, and especially to direct the current to the 
points intended, and their efle(;t will depend upon the skill of the engineer. If they are once built 
on this plan they will last through all future time. 

Direction 2. 

The river must be confined to a width of half a mile. The confinement by the jetties and the 
distances between their points must be proportioned to the size of each river. The Missouri for a dis- 
tance of a thousand miles above its mouth must be confined to about a quarter of a mile in width. The 
Ohio, Arkansas, Tennessee, Eed, Kansas, Cumberland, Washita, and Yazoo, and such rivers as the Eio 
Grande, Alabama, Brazos, and others, must be contracted to Avidths of from 100 to 250 yards, or to 
widths proportioned to the A'olumes of their waters. Channels should be blasted througli the ledges 
of rock forming their falls and shoals, and dams of cribwork of wood and loose stones couA^erged 
upon the channels to proper distances and at suitable angles. Cribbed-stone jetties must be applied 
where piles cannot be driven. 



40 CONTEIBUTIONS TO THE 

To effect this confinement of the Mississipjii from Cairo or Saint Lonis to the jjasses, it will 
not be necessary always to run the jetty points within a quarter of a mile of the central line of the 
channel they are intended to erode, but they should never approach each other nearer than a half 
mile. Where the river is very wide, shallow, and straight, it will sometimes be necessary to place 
them opposite to each other, and to converge their lines to a distance of half a mile between their 
points. But often short jetties, properly angulated, will greatly reduce the width of the river below 
them. In every instance where a i^roperly-constructed jetty is run into the bottom current at an 
angle of 45°, it will deflect the current entirely across the bed against the opposite shore, unless 
the current deflected from another jetty extended from that shore strikes it diagonally before it 
reaches it. This is an important fact which should never be forgotten by hydraulic engineers, who 
must be required to mingle the currents to prevent either of the two from reaching the shore opposite to its 
location. The main object is to form them into an accumulated eroding current to deepen the bed, 
and to make batture against the banks. A proi^erly-constructed jetty on one bank will certainly 
destroy the bank on the opposite side against which it points the current, unless another is suit- 
ably placed for its protection. 

Direction 3. 

Where it is necessary to scour a deep channel nearer one shore than the other, as in the case 
of a city front with its wharves, the jetties above the wharves must be deflected from the bank at 
very small angles, while those which guide the water from the opposite bank must have angles more 
obtuse, and in some instances they must have the maximum angulation of 45°. It must be remem- 
bered that the minimum angulation in all cases is 11^°, and the maximum 45°, which is easily dem- 
onstrated by experiment. The angles of jetties to turn cut-offs like that at Vicksburg, aud to close 
them, or to stop crevasses, must always be angulated from 22J° to 45°. (See Plate IV, Diagrams 
1 aud 2. 

Direction 4. 

Toprotect islands, construct at the upper end of each a V-shaped jetty with its point up stream, 
which will part the river current and deflect an eroding current toward each of the opposite banks. 
The eddies around the mngs of the jetty will enlarge the island continually, while the currents 
which these wings deflect will undermine and destroy the banks unless jetties are iilaced upon 
them to catch the deflection and reflect it to a safe distance. If it is desirable to enlarge the island, 
the jetties on the oj)posite banks should be so angulated as to mingle the currents below it. It 
will extend until it reaches the point where the converged waters meet. If it is necessary to 
destroy the island, construct jetties on both banks above and opposite to it, to guide the currents 
against its sides from the upper to the lower end. 

Direction 5. 

To close a cut-off, bayou, or crevasse, first construct a jetty above it to deflect the current from 
its outlet from the river and form an eddy in it, and, if it is necessary, which will seldom be the 
case, assist the operation by a row of piles and fascines if it is shallow, or by sinking into it a con- 
nected raft of large trees with all their branches upon them down to the bottom if it is deep. I am 
not prepared to say i)recisely where such a work should be constructed to restore the river to its 
lormer channel in front of Vicksburg, as I have not examined the locality since the river has cut its 
way through the neck of the peninsula and left the city on the eastern curve of a crescent lake, and 
I have seen no chart of it since the destructive change occurred; but I am very confident that one 
or more jetties, constructed as all jetties should be, at loio water, and at a suitable point on the right 
bank above the gap made by the new channel, would turn the whole river permanently against the 
rocks of the left bank and into its former bed. I cannot giv^e an estimate of what it would cost 
the United States Grovemment to make this improvement for this important harbor, as I have seen 
no topographical surv^ey of it since the disaster happened, but I do not think that it would be 
much. 

With this general outline of the titanic plan for chaining the mammoth river and utilizing its 
mighty current, I will close this essay, which I fear has been tedious, notwithstanding the omission 
of all specific details not necessary for its explanation. 



SCIEIs^CE OF HYDEAULIC ENGIKEEEING. 41 

To lower the whole bed of the Mississippi effectually, the lowest bar should he removed first, and 
then those above should he destroyed successively or simultaneously as high up as it is proposed to make 
it navigable, and to prevent its inundations. The river current, compelled to act permanently in a 
fixed channel, will deepen continually from age to age until its bed is conformed to the general 
>-lope of the continent from its highest navigable tributaries to its mouth in the Gulf. The iuclina- 
tion or dip of the strata of its bed-rock from the mountain crest to the deepest depressions of the 
Gulf determines the angulation of this slope. It would be madness to straighten its curves. Its 
velocity, caused by the earth's revolution on its axis, with its centrifugal force acting directly upon 
its vast volume, hurling it directly from the direction of the North Pole towards the Equator, would 
render it uunavigable and uncontrollable. Bends, changing this direct or rectilinear action, check 
its force. Our object should be to give flxeduess to property on its banks, and to increase the area 
of its arable alluvial soil while we prevent its overflows, and at the same time make it safely and 
permanently navigable. 

The excellence of this plan for controlling water-currents directed to cut channels of geometrical 
shapes by properly angulated jetties is made apparent by experimeut. 'No dredging is necessary 
where the materials of the bottom are not more solid than the alluvium of the ri\^ers and the sands 
and clays of our southern shores. In all places where these jetties are properly applied to make 
either river or sea currents deepen channels through such materials, iu almost every conceivable 
instance of their application, they will form areas of batfuro, or new land, which will be worth much 
more than the eutire cost of their construction. In order that these principles may be better 
understood and applied, I have directed the attention of engineers to the Mississippi, Lake Pont- 
chartrain, and a few other ijofnts for the ijurpose of illustration. But if they possess ordinary 
genius, with even but little invention, thej" can easily vary and apply the same principles of angula- 
tion and eJcnmzesis to any river, harbor, or marsh where there is water to employ and control. They 
who still cherish the absurdity taught me in my boyhood, that water, unlike other fluids comi)osed 
of globules of atoms, cannot be reflected, of course cannot understand them, and will not attempt 
to utilize them. 

CONCLUSION. 

If the facts which I have presented, with the theories based upon them, in this essay, have 
given it the appearance to some minds of a harsh criticism uxjon the plans of hydraidic engineering 
appUed by Sir Charles Hartley and other eminent engineers to the rivers and harbors of Europe 
and America, I say in all sincerity that I have not intended to detract any ray from their deserved 
renown, or to diminish the debt of gratitude due to them by mankind foi' their useful services. My 
object has been to give the improvements to all plans for controlling and utilizing the currents of 
rivers and seas which newly-discovered facts and useful inventions have suggested. I honestly 
desire to facilitate the tasks of these meritorious laborers for the welfare of the world, and to save 
them and those who will succeed them from much unnecessary toil and expense in their operations 
by presenting them with improvements Avhich will make similar works, and others on a grander 
scale, cheaper, easier, and better. The latest discoveries made iu the science of zoology, and in 
the arts of photography, telegraphy, and steam navigation only enhance the tame of Ouvier, 
Daguerre, Morse, and Fulton, and render their memories more dear to all iiations as benefactors of 
the human race. I will on]y add that I tested all these inventions for controlling and utilizing 
water-currents, and which were made iu order to cheapen the vast and permanent works for which 
they are designed, by the most careful and satisfactory experiments before I ventured to publish 
them in these lectures for the Avelfare of mankind. 

May the God of all wisdom and power give them grace to use theiu wisely and successfully. 
6 H E 




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CONTRIBUTIONS 



TO THE 



SCIENCE OF HYDRAULIC ENGINEERING. 



BY 



EAV^D. FOISTT^IISrE, 

PROFESSOR OF THEOLOGY AND NATURAL SCIENCE, MEMBER OP THE NEW YORK HISTORICAL SOCIETY, 

THE HISTORICAL SOCIETY OP MARYLAND, &o., AND OF THE ACADEMIES OP SCIENCE OP 

BALTIMORE, NEW ORLEANS, &C., AUTHOR OP "HOW THE WORLD WAS PEOPLED," &c. 



WASHINGTON: 

GO VKllNMENT I'llINTING OFFICE 
1<S7 9. 



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